Hi all I am wondering if anyone here could tell me the proper weight thread for saddle stitching knife sheaths. I am using 7/8oz shoulder veg tan tooling leather, a groover, and a a #5 stich wheel. 
After placing my welt in place Igroove and lay the stitch marks and use a 3/32 drill bit on a drill press to make my holes.  (I know, I know....I should use an awl). 
What is the proper weight and or type of thread for this application? 
Many thanks in advance.