Then I'd say 'go for it!" Pick. You'll have safe loads and may have to sweep a line of unburnt powder out of your barrel. You also may have to go to a hotter primer, and I'd definitely crimp the bullets with as heavy a crimp as the die provides.
As far as relative cost goes, don't compare the two powders' cost canister-to-canister or even pound-to-pound. The cost of each load is the true index of which powder is cheaper to shoot. Four times as much powder per charge, at half the cost per pound, is not economical. Figure and compare the costs per charge or per hundred charges.
