I'm not sure what you mean by variable seat recline. I'm planning on
making the seat adjustable within a reasonable range (approx 30 +/-5
deg abovr horiz for the hip-shoulder section of the seat, upcurved top
to limit neck/upper shoulder strain) using a similar system to a
t-bone. My current drawing puts the BB center at about the same level
as my hip joint when seated (a few inches above the seat base).

Speed at all costs is not my primary goal but the thing needs to be
fairly fast and also climb reasonably well. This is more fast tourer
than racer. My primary design consideration is to optimize this bike
for my commute. It need to handle traffic adequately when needed. It
needs to be fast on the flats and it needs to climb reasonably well.
My morning commute consists of a long gradual downhill which I usually
maintain about 25-30 on on the road bike. followed by a streatch
through town which is all stop and go. Then a ~10 mile streatch of
flat to rolling hills which I maintain about 20 on the road bike, then
a 3 mile climb (2 - 10%) , a 2 mile downhill and a 1/2 mile climb (4 -
15%). Avg speed on the computer is usually a hair over 16mph avg. at
the end. If I can match that rolling avg on the bent with a bit of
practice, I'll be happy. I'd rather gain a bit of speed on the flats
in exchange for a little climbing ability since the flat roads are
heavily travelled and the faster I am, the safer I am.

-Tim