Going to be using 3 peice cranks or the 2 peice cranks(External BB)?
If your going to be using a crankset designed for an external bb, all you need to know is the shell size and since most external cups are universal fit they come with bb spacers to fill in the gaps. Most 2 peice cranks have the same spindle length*
If you're going to use a 3 piece setup, there is a reason why there is a tech section where they will provide you an email address to contact them with technical questions. I'm going to guesstimate the bb size you will need is a 68mmx115 for that frame.
*The only case with this setup where spindle length is a concern is when the rear spacing on the frame is 150mm, not 135. Which isn't a concern for you. If it was, you would have to look for a 2 peice crankset that can handle 150mm rear spacing.