TRV / Old Rad Spud is Xtra Long / Valve Xtra Tall

ThomasEwing

I have pipe fitting questions. I would like to install TRV's in my 3rd floor. If the boiler runs long enough to heat the first floor, I waste a lot of heat upstairs. The rad old valves (mostly original) no longer modulate. 300 MBTU (right-sized) WM Ultra in 6,000 SF house from 1895. B & G circulator, etc. per this site's recommendations, but it's a single zone system. Originally a gravity system, so the pipes are large.
Some rad spuds are longer / some rad valves are taller than the TRV's (or modern rad valves).
1) Any easy ways to get extra length between the rad and the TRV?
2) Any problem with using bushings on the rad valve side to reduce, say 1 1/4" to 1", while leaving the old 1 1/4" rad elbow intact opposite?
3) Am I playing Russian Roulette trying to remove the riser nipple from the (xtra heavy weight) fitting below -- 1895!