Poste this elsewhere, but I do need help with .470 reloading. I am in south america and cannot bring powder and primers into the country easily (a major understatement)

I have a few old Remington 91/2M primers and a single base powder CBC (magtech). This is their slowest burning powder and is called CBC 124 used in 300wm and 7mRM.

Today I tried a few 500 grains woodleights throug my cronograph:

90 grains +12 grains filler = 1747 fps

95 grains +10 grains filler = 1801 fps

Federal factory = 2049 fps

Question 1: is this remington primer much worse than the 215?? So that I will never get good results??

Question 2: was 50 fps to little for a 5 grain increase in powder? Is this powder no good?

Question 3: as I increase the charge, how much can I compress the powder?