For measuring inclination and declination, a Suunto clinometer is invaluable. I use one in target archery, getting a hard and accurate reading rather than relying on an electronic device to get you close is extremely useful, especially for yardage cuts.
For the rest, print off some charts, maybe more than some, and go shoot and verify. Shoot in the worst and best weather you can find, different altitudes, temps, wind, etc.
There’s really no way around verifying your dope cards other than sending bullets downrange. It either hits or it doesn’t. I’ve always just printed off a good number of them using JBM to get a range of cards, found the ones that line up best, clearly label and laminate. Do the same for every new locale you can shoot in, and be sure to record all pertinent info.
Used to be, you’d see shooters with dope cards taped to their rifles, and that was the norm. There are other ways to do everything, this is just what I did/do.
Ballistic computers have made this stuff a hell of a lot easier.