I figure that Sabotloader would do better than Hodgdon with the 410. I have found hodgdon's data somewhat conservative, but then every rifle is different and I suspect powders vary a little by batch (mostly in weight per volume)

Since you liked that one cayugad. Here is another trick. Say you want to increase or decrease the charge and want to know how that will affect muzzle velocity.This works especially well with black powder, but as works fairly well for subs.

Say Sabotloader gets1390 with 70 grains.How much with 80 grains? Just think of powder as energy. The muzzle energy per unit volume of powderwill depend on the projectile chosen. The greater the weight of the projectile the more energy one gets at the muzzle for a unit volume (grain) of powder.

One just takes the ratio of charge volumes. Or 80/70 = 1.143. There is 14.3 % more powder in the 80 grain charge. This means there is14.3 % more energy in an 80 grain charge. Since Sabotloader gets1974 ft-lbs at the muzzle with 70 grains, he should get 14.3% more muzzle energy with 80 grains or 1.143 * 1974 = 2256 ft lbs.

This corresponds to a muzzle velocity of 1486 fps in Sabotloader's rifle. I figure thats pretty close.