L, M, H. Low, Medium, High. There's about 2# difference between them. If 5M limbs yield 70# then 5L would be right about 67 or 68#, but being as most bows go over the max by a pound or two then 5L might just give you 70# anyway. If it doesn't then it's simply a matter of adding a few twists to the cable(s) to bring that weight up to snuff.
For instance, on the 2012 Nemisis I got this year with Barnesdale limbs with a 175 deflection it was supposed to be 50# peaked, but actually came through at 54.1#. Granted these were Barnesdale limbs but the application is the same with Martin limbs.
If You're Not Living on the Edge You're Taking Up Too Much Space
Martin/Rytera Staff Shooter
PSAA Life member, UBP Life member
PADI AOW Diver