U have two ways to fix chainlines... one is to move the crankset or move the hub/cog. A 103 BB is pretty short, i didn't even know there was one in jis that short (remember dura ace 104 and 107), as long it doesnt hit the chain stay you should be ok. Now the rear wheel, the easiest to fix a problem in the rear w/o having to respace the wheel and re true the wheel is to use BB spacers. If you need to move the cog out a few mms, just go to your lbs and ask them for BB spacers, they should have tons of them. Put that between the hub and the cog and you are done.

Chainlines do not have to be 100% perfect, besides the chain gives you a slack also so you should be ok. If you bought a BB sealed unit that is too short and you need to move the crankset out a few mms.. do the same thing... put 1 bb spacer at the right side between the shell and the cup and you are all set.

Good luck.