John,
I just love your "Covid" project (20m rig and amp)! Just wonderful!
I almost exclusively operate 20 meter phone. Have a good feel for the band. However our club may be doing a special event in a couple of months, including one station on 40M phone. I'm open to suggestions as to best portion of band and any other ideas for operating 100W with modest wire antenna. Location will be Kansas City, for the NFL Draft.
In addition to the 40m SSB tips, you've already gotten, here are a few more that might help.
Of course, your local noise level (local RFI) will probably be your limiting factor there....as it is everywhere these days, huh...but, assuming you don't have S-9 RFI, you should have fun!
So, here are my tips on Propagation:
If you're operating 40m SSB during the daytime?
100 watts SSB and a simple dipole. or inverted-v, at ~ 30' - 40' high
(of course, even higher would be better), with our increasing sunspot numbers the D-layer absorption will be fairly high, so you'll have good signals throughout most of the central CONUS, but midday 40m signals from farther away will be weak or nonexistent.
{Think of most of the US central time zone (and some of the mountain time zone) will be good during the daytime (actually day and night)....with eastern time zone coming in late afternoon.....and, the rest of the mountain time zone and western time zones, coming in early evening / near your sunset.}That means fans from K.C., Minnesota, Green Bay, Chicago, Indy, Nashville, New Orleans, Dallas, Houston, Denver, etc. should be within your range on 40m SSB (w/ 100 watts and dipole) all day/night....along with some decent comms with Cinci, Atlanta, and then Detroit and Cleveland, especially in afternoon and later.
With Pittsburgh and Philly, Buffalo, Carolina, Jax, Miami, Tampa, Washington, Baltimore, NY, New England, etc. should be good in late afternoon and throughout the night.
Then Arizona, Las Vegas, Los Angles, San Fran, and Seattle coming in early evening and all night long into your early morning...
If you're looking for NFL "Dx", Mexico on 40m will be open similar times as western / mountain time zones....and, the UK might be possible from an hour (or so) after your sunset up until 1am CDT?
Other Dx might be possible, depending on your local noise level, your antenna, and propagation at the time.
I hope this helps.
Good luck and have fun!

73,
John, KA4WJA