I'm trying to use and old triple crankset for a fixed conversion. I have the chainring mounted inside with 3mm spacers. The measurement from the center of frame to the center of the ring is 45mm. The cog is about 40-41mm from center. I'm using a Shimano 109.5mm BB(octalink). There's only about 3mm between the crankset and the BB.

I can't move the crankset closer, there aren't any spacers on the hubs(Miche) to move around.

What are my options? I don't have a chain yet to test the chainline, is 4-5mm difference too much? Should I be looking for a double crankset? will that make any difference?