Since nobody has chimed in I will give it a shot. I hope I won't totally mess this up, if so someone please correct me....
I think the kits are pretty much the same. Difference was if you ordered from Les he would throw in the needle he thought would compliment your riding style and altitude. I think he marked the kits -1, 0, and 1 to identify the needle he supplied but I'm not totally sure. They were aftermarket needles, probably the same that JD uses but he would polish off the ID marks (CCK, CEK, etc). LTR doesn't supply these kits any more although there may still be some available through GoFasters and other dealers.
Another thing Les was good at was customizing the jets he supplied for your riding style and bike. My '00 XC250 uses jetting larger than most anyone else here on this board, even 300 owners. 48 pilot and 180 main. He knew that. I would never have gone that high with the pilot by experimenting as it acted like I needed to go down from the 38 pilot it came with.
A few here have used the JD kit and I don't remember hearing anything negative.