Hi y'all! Thanks in advance for any help. I'm pretty much a novice when it comes to the fixie world of bikes but I've always wanted to build one.

So, I've got an early 70s Schwinn sports tourer, the derailers were shot and I removed them. I set it up to run as a " single speed" using a freewheel and a few cogs for the time being. With a front chainring of 54 and the correct length chain I can run a 15, 17, and 20 tooth cog on the back just by manually switching the chain and adjusting where the wheel is located in the dropouts. The chainline ain't perfect but I'm just fooling around right now. I want to make a more permanent and proper setup for touring.

What I'm really wanting to do is set this bike up with a flip flop hub with as many gear selections as possible. I would like to use the 54 chainring and two or three fixed cogs (14, 17, 20 T) on one side and the 40 T chainring with a two or three cog freewheel on the other side (not sure what size cogs yet) that would utilize cogs to fit the same chain. I want a tall geared fixie side for long rides on the prairie and a lower geared freewheel side for when I'm tired or in hilly areas or just cruising around town.

Is there any way to accomplish this feat with off the shelf hubs and cogs? The local bike shop said no. Sheldon Brown has done a three speed flip flop...

Thanks!