The 8200u is also wider because of the reception elements it has to cover the full VHF spectrum of the lower broadcast channels 2-6, FM, and upper channels 7-13. But after the DTV switchover the lower VHF broadcast channels have been mostly abandoned around here. (I think there are a couple of out of state LP DTV stations operating on VHF 5 and VHF 6 down in Maryland.)
And the HD7694 only covers the upper VHF broadcast channels and UHF channels 14-69 (anything higher than UHF 51 is now relegated to low-power analog broadcasting) which makes for a more compact design both in length and width (which gives it a smaller turning radius) than the "all-channel" 8200, but from a "reception mileage" rating, it might be a little on the small side.
So you might want to compromise on an HD7697P. It has a boom of 131" (vs. 168"), a max. width of 53" (vs. 110") and a turning radius of 81" (vs. 101") and with a "mileage" rating of 60 miles is just marginally less than the 8200's 65 mile rating.
And don't think that by sticking an amplifier on the 7694, it would make up for it. Amplifiers are only useful to overcome long cable runs, or for providing an input signal to multiple reception devices.