Another resource, that I more often see mentioned in the "Alt Bikes" forum:
https://www.atomiczombie.com/
(Note: I've not used them, so I point out the resource, but can't recommend/ disrecommend their plans, either.)
Extra weight won't make much difference in a flat area, but will work against you in a hilly area.
It seems like all the "fast" bikes I've seen, upright or recumbent, generally used 700 wheels, not sure why that is. Other things being equal, it helps if you can use the same tires and tubes as your other bikes and same as other riders.
A fairing may work against you in a hot climate, but work better in a cold climate.
Years ago, I used to see a local rider in a fully-faired recumbent with homemade fairing out of coroplast. He liked it, but wasn't especially fast, either, so I'm not so sure it really helped him.