hi,
a moist nest box, like a little rubbermaid tub with a hole on the side, and a couple inches of damp substrate, like that coir stuff (coconut fiber brick) could not hurt anything. and it might help. if the young are sucked dry by the aspen substrate and atmosphere they might not be able to get out of their birth sacs and get exhausted and dried up. most snakes this killed would probably be doomed anyway, born losers, but you never know. if you lived some place like wyoming (dry, dry air) it might matter. i've lost a couple of runts or below-average-size neonates like that over the years (but they were probably born losers...). anyway, like i said, couldn't hurt a thing. a comfy, minimum-stress birth will only help any young you might get. in any litter you'll get variance, some big and strong, some not quite so, and maybe a weakling or 2. it's fun to have them all make it, even if they're "just copperheads" (i love copperheads).
cheers,
jimi