It probably won't make a big difference.  In fact you may even wind up with a better match if fed off center - particularly if the antenna is fairly close to the ground.  I don't think you will need the balun.

I typically use a 50Hz filter when operating on psk31 and usually experience little or no QRM from nearby signals. I don't think an SSB signal would have much effect on a psk31 station or CW station employing a decent narrowband filter.

I was on 60M two nights ago, made several CW QSO's on channel 1 and heard several others.  No problems were noted.  Heard no SSB on channel 1.  My prediction is that channel 1 will eventually become the de facto CW/digital channel.  Sure would be nice if one could operate anywhere within the channel boundaries when using a narrowband mode.

It really seems stupid that users of narrowband modes all must operate in the exact center of the channel.  It would seem that the FCC has no interests in "best practices" or spectrum conservation.  I'd love to hear their justification for requiring the practice.  Maybe there's something in the beltway water supply that destroys common sense.

If you do a decent job installing the 5-BTV you will have no need for a tuner.  If you ground mount it in the clear with 30-40 radials each about 20-25 feet long it should work quite well.  Band width will only be 25 or 30 khz on 80 meters so pick the frequency where you tune it for 80 carefully.

I'm not a lawyer but the thing certainly seems to speak for itself and what it says seems to be good news for you!

Sorry, didn't realize you wanted to make this thing really short.  I redid an EzNexc simulation using an inverted vee with apex at 30 feet and each end up 10 feet and out 22 feet from the center (leg length 28 feet).  113 uH coils placed 7 feet from each end would result in an SWR of about 2.34 at 3.850.  As another station suggested, you might consider also using a tapped center coil to get a better match in conjunction with outboard loading coils. 

As mentioned earlier, you need a loading coil - not a trap - to operate the antenna only as a shortened 75 meter dipole.  If you download the free demo version of EzNec you should be able to calculate the inductance of the loading coil depending upon the overall length of the antenna and how far out from the center you wish to install the coils.  The further from the center you place the coils, the more efficient the antenna - BUT the coils need to be larger when you move them out further.

I ran some quick calculations to give you an approximation.  It you make your antenna as am inverted Vee(45 feet on each leg) with the apex at 30 feet and the ends at ten feet up, you would need at 55uH coil on each leg placed about 11 feet from each outboard end.  Estimated SWR would be about 2.5:1. at 3.85 Mhz.

To finesse (somewhat) the substance of your original question which seems to boil down to "How can one operate in a very high noise area?" - I can offer little in the way of antenna-based solutions.  A different approach to the problem might be to consider modes of operation that are less susceptible to noise in the first place.  Olivia, MFSK, CMSK and several other digital modes (not psk31) come to mind that can work rather well under high noise/weak signal conditions.  It might be worthwhile exploring the use of such modes with whatever existing antenna you have.  I wish you well in your efforts to get the power company to solve your problem but don't hold your breath.

Try one inch and see where that moves it to.  Then you'll have a good idea how much more to trim to get it where you want it.  You might have to lengthen the 80 meter portion of the antenna a small amount to get it back where you want it.

I've used several LDG AT-200 Pros with my TS-480HX.  Had one of them get cooked while running about 70 watts in one of the high duty cycle digital modes.  LDG repaired it at no charge. 

I also have an MFJ 998 1500 watt autotuner that I use remotely when running high power.  Other than the fact that it seems to get "confused" once in a while, it works fine and handles 1200 watts on CW with no problems. 

I think the MFJ autotuners are as good as anything else thats out there.

I described the "Lazy 7" fly-by-night antenna in a recent eHam article.  It consists of a 23 foot "flagpole" used on 40 thru 10 during the day and on 80 and 160 at night by the addition of a top loading wire and coil.  I live in an HOA and must resort to "stealth" techniques. 

The recent CQWW 160M CW contest provided a good opportunity to evaluate the Lazy 7's performance on 160.  During 14 hours of operation 310 QSOs were completed in 44 states, 6 Canadian provinces and 22 countries - including HK0NA (Malpelo Island).  Had my contesting skills not deteriorated from approximately 25 years of neglect, the results might have been better.

This antenna's performance is certainly less than competitive with the performance of many other antennas in unrestricted situations but it turned out to be considerably better than expected. 

Don't let antenna restrictions keep you from getting on the air - even on 160 meters!

When pigs fly.

If it makes you that unhappy, why not do something else?

Ditto re: Fldigi.  Very user friendly, comprehensive digital mode program.  Have been a user for about 3 years and love it.

I'm not familiar with your tuner but most tuners have an output for a single wire that usually involves a jumper.  Follow the tuner's directions for a single wire. 

Yes a counterpoise should help things.  You might be able to get away with the station ground.  I'd try it with the station ground first and see if reception improves.  Should you decide to go further you can install a ground rod outside just beneath where the ladderline is terminated and run a series of radials to that point.  Don't worry about the length of the radials.  Make them as long as convenient and run as many as you have patience for!

Yeah, I'd short the ladderline  I'd disconnect the balun and run a single insulated wire to the shorted ladderline and hook the wire to a tuner.