Well, I thought I had all the parts to allow progress. Ooops.
Drilled the "nut" portion of the two lower fuselage fuel drains so they could be mounted. Not a perfect pretty drill, but good enough for the wire to go through, so more importantly, the drain *should* not fall off in flight!
I had previously marked the two locations in the fuselage for mounting the drains; they fit on the underside, but a "tee" on the top side accepts the threads, locking both in place. Drilled the holes first using a pilot drill, then a step drill up to the 7/16" final size. Got out the tees and....they were supposed to be the type with two 1/4" NPT inline holes and one 1/8" NPT hole on the bottom to match the fuel drain. All 3 were 1/4" NPT, so had to order new parts. *sigh*