Lol at converting fixed bikes to geared. I thought the cool thing was to convert geared bike to fixed...

Also, lol at "I've been running my '09 Mercier Kilo TT as a singlespeed freewheel bike for years, but frustrated with the need to flip flop my track wheel to the larger sprocket side just to climb hills..."

Buying the right thing designed for what you want is just to hard...