ArizonaSlinger,
Welcome back!
Did you used to be known as Almulek? I found your old posts ... 33 posts under that name, including the one where you recounted seeing Knollslinger put a stone almost through two sheets of plywood (but I don't know how thick the plywood was -- I'm guessing half-inch?).
Hey, 'way back then you asked Knollslinger for advice on making a sling like his. Your experience sounds very much like mine ... I made a Knollslinger-style sling out of deerskin leather; I cut the pouch out by tracing around a credit card, punched holes in the corners (about 3/16-inch from the edges), threaded my paracord through each side. It worked quite well. The holes in that pouch have stretched some, but never torn.
I read somewhere that deerskin is considered one of the strongest leathers as far as tensile strength is concerned (and if you are interested, kangaroo leather is considered stronger than deerskin and also resists abrasion much better -- a company called David Morgan, in Washington, sells kangaroo leather goods and also tanned skins for those that want to make their own things --
www.davidmorgan.com).
Do not worry about absenting yourself. I've been here just over a year, and most of us seem to phase in and out. I shot my mouth off quite frequently in my early days, but I don't post a lot any more. I asked Chris about this, and he confirmed that most folks seem to do the same. Some just disappear, maybe they lost interest in slinging. Some seem to just read for a while unless they discover something they think worth sharing.
If you hear from or see Knollsinger, say hello from us and let him know that we still think about him. I don't think anybody has a way to get a message to him except through this forum, however.