So far I've had 100% success with the following on my gravel wheels:
Remove valve core, install tire with tube
Inflate and get both beads to seat all the way
Deflate, unseat one bead, CAREFULLY remove the tube leaving the other bead fully seated
Install valve core
Set the wheel horizontally on the ground with the open bead down, so gravity helps a bit rather than hinders
Carefully tug on the tread to get the open bead as close to the rim as you can. You might be able to set about half of the circumference all the way into the bead.
Pump hard
But there's such a wide range in rims and tires, best you can do it try and see what happens. If you're in the market for a new floor pump there are a bunch now with air chambers you can compress with the handle then release in a burst, this makes a lot of sense to me.