Thanks for the review. I haven't tried Challenge gravel tires; but I may try them. I've been riding my 35mm Compass Bon Jon's with Challenge latex tubes for over 2,000 miles on mixed dirt roads and pavement at 35/30 PSI. No punctures (maybe I'm just lucky). But, I sometimes would like a more aggressive tire like the Challenge Gravel. I have mixed feelings about tubeless. On the one hand, I've been running Ramblers and Gravel Kings tubeless, also without issues. On the whole, I've found that tubeless tech. is fairly simple and easy. No big deal. But tubes- especially latex seem to perform as well for me; and less hassle.
Which latex tubes are you using in a size big enough for gravel tires?