Ken, interesting finds, that is a really handsome "Yuma" morph (dark with thin bands) California common king snake. Tucson area king snakes are highly variable with gene flow from Cal kings, Black kings and Sonoran desert kings. I get Sonoran desert kings down here, about 120 miles south of you. I would love to see photos of the kings from your area should you be inclined to send them. Do they all look pretty much like the one you posted?
I think that is great you release snakes when you can, and I won't use nylon/plastic netting anywhere near the ground for that very reason, it is a real wildlife killer. Snakes are so vulnerable, they get caught and do the worst thing, twist and turn and the nylon becomes a ligature, cutting into them. As you indicate, when in the sun, the merciless sun rays finish the torture and they overheat and die. Nothing deserves such a fate... I did not know they would entangle in poultry galvanized type wire fencing material.
Regarding the mortality rattlesnake, I think your original ID is best, I think it is C. atrox, diamondback. Most, not all, mojaves's are a greenish brown tinge more so than grey, but if you are close and can look at top of the head, you will Mohave rattlesnakes have large shield like scales between the eyes, rather than the fine small scales between eyes of diamondback. Either one are serious, don't get bitten...especially by Mojave.
Using the tube to restrict movement of snake is what many biologists do in mark/recapture/telemetry studies with rattlesnakes. Please be cautious, a mojave bite is just too serious.
Thanks for posting, that is a really nice king snake (although I never met a snake I did not like)
Vic
Hereford, AZ
Zone 8B, Chicago Hardy, Excel, and big plans for the future