Hey there Jimbo, welcome.
I've never used or seen GOEX cartridge powder. How does it compare in granulation to FFg and FFFg?
As and experienced sidelock shooter you should have no problem working up a load for your Pursuit. The Pursuit's 1:28" twist is faster than what you're used to with sidelocks, giving you a lot of options with saboted bullets.
A lot depends on what you're targeting as a maximum hunting range. If you're talking 150 yards or less, you can't hardly go wrong with any of the popular bullets (Hornady XTPs, Speer Gold Dots, Barnes) in weights from 240 to 300 grains. Powder charge pretty much depends on your recoil tolerance and what your gun likes. I've been shooting 300 grain XTPs and Gold Dots in my two in-lines, using Harvester H5045SB sabots and 95 grains of GOEX FFFg with real good results.