Good point about the fixie gear with long cranks. Freewheel is the only choice.

At first I decided to try and buy a track rear wheel with a flip flop hub. Then I decided to look into a Shimano freehub to single speed conversion kit which includes spacers to get the spacing on the freehub right, because i have two rims to mess around with, one with a freehub the other freewheel. Then I realized I would need a proper single speed chainring, and probably a single speed chain.

in the meantime, should I just play around with the front chainring orientation, take some links out my 9 speed chain, pick a gear on the rear hub and tighten the chain using the horizontal dropouts?

I know this is a bad idea, because these gears are obviously designed to allow the chain to easily slip from cog to cog. So would I gain and benefit from doing this temporarily to just play around with the idea and see how it goes?