InsaneDiego - Sorry I missed your post and a bit late with a response. I have always used generic HD motocross tubes in both tires. I run 15 PSI front and 10-12 PSI rear for all off road riding. In the rocks and hard terrain I'm not aggressive with hard hitting riding. So pinch flats are very rare. Cactus tines were a much bigger problem when I was riding in AZ.
As for the rubber thickness on tubes, I've not measured it. I can tell out of the box they are heavy rubber. Good enough for my riding. I always check for leaks before installing HD tubes. I had several leak where the valve stem enters the tube. Sometimes the pinch bolt on the valve stem is loose too. I've had valve cores leak and/or be loose. Yes, on brand new tubes. As for brand, I will always buy a recognized name and select a premium grade. The few extra bucks you'll pay avoids problems I think by getting you better quality.
The HD tubes are more difficult to tuck into the tire. I will install tubes first by poking the valve stem through the rim. Then I'll work the tire over the tube there. Tuck the balance of the tube into the tire and pry them both over the rim. Check the rim tape and make spoke nipples are in place. There rear tires always SUCK! It's a job I hate.
The trick with this method is making sure the tube doesn't get pinched between tire bead and rim. If you're careful this won't happen. Watch the bead lock too making sure it's all the way in the tire cavity and not pinching the tube. I'll inflate to 35-40 PSI to set the bead then back down to 10-12 PSI.
Lubricant like soap or WD40 really helps when prying the tire on/off. I use 3 spoons and get Jeannie to help hold the 3rd. I'm glad when the job is done. Hope this helps.