I'm going for a saddle stitch with a nice angle to the stitches.  I understand that a groover will straighten the line out significantly, so I'll be using a scratch compass (spreaders?)  to mark my line. 
My question is this: 
If I'm using an awl to make my holes, does it really matter what I use to space them out with?  Nice expensive handmade pricking iron, or a cheap Tandy punch that I simply don't hit all the way through?  If it is only marking a place to put my awl, and not making any hole, then it seems (with my limited knowledge) that it shouldn't matter, and therefore pointless to spend big $ on this tool. 
Please correct/confirm my thoughts.