SD,

There is no easy answer to this question. It all depends upon the crankset and frame. Each combination can be different, thus requiring a different length BB spindle. The other factor has to do whether you are using a double or a triple.

My suggestion is to decide on the crankset you want to use, buy and install the adapter, then take the frame and crankset to an LBS and see if they would like to help you fit the two together. If they are not friendly about helping, go to another. My guess is they should not charge more then 1/2 hour for labor plus the cartridge BB (about $25 for a Shimano UN 54, less for others).

Best of luck.