Thought I would share an update...
Well I spent Saturday crawling around my attic putting in 5 dipoles for 40, 20, 17, 12, and 10 meters. Used Bob's (K7JQ) suggestion and used an RCS-10 remote antenna switcher and coax to the shack into my MFJ-993B autotuner. Powered up the antenna switch in the shack and started listening to both my outside OCD and the attic dipoles. Major disappointment at first! I could hardly hear anything on any of the dipoles. After some troubleshooting, I discovered that I had not attached the ground wire from the remote unit in the attic to the switch in the shack. Night and day difference!!!!
Did a lot of listening and my first contact was with San Juan on 10 meters (my qth is Indiana). I'm probably wearing out the button on my autotuner switching between the OCD and the attic dipoles.
On some bands, I'm getting better reception on the dipoles with less noise. (not sure what that says about my OCD) The OCD runs East / West and the attic dipoles run North and South. My house is an L shape and the dipoles are over all of the garage and 2 bedrooms. The dipoles are in a V configuration with the center up about 12 feet from the attic floor (ranch house). There's no ductwork up there and only regular house wiring. So far, no RFI issues.
So far I'm extremely happy with attic antennas going into it with somewhat low expectations. I'm going to do some testing but I'm thinking that with the autotuner, could I have just gotten by on the 66 foot long 40 meter dipole? That might lead me to reorient some of smaller dipoles in different directions. Also I'm thinking about an open or closed loop. I have the wire and I have 3 open ports on the atnenna sitch so why not, right?
Bottom line for me... Attic antennas on 100 watts work!!!