You’re going to need a sizer of some sort at a minimum. If you dive off into the world of powder coat you can use cheap push through sizers that fit your reloading press.
If you want to traditionally lube and sizer you need a lubrisizer. Lyman, Saeco, RCBS, Star, and others make/made sizers. I greatly prefer the Star but they are no longer made and neither are the dies.
Gas checks will crimp on when you push the bullet through the size die, no need for a separate operation or machine.
429215 is a Ray Thompson design and like the heavier 429244 of his it is a good shooting bullet when cast and sized properly. But at 44 magnum speeds I don’t use gas checked designs very often as with proper fitting bullets made of the correct alloy they are unnecessary. I probably wouldn’t base the purchase of a gun on a $50 mold unless it was something I was already interested in and planning on anyway, especially if I didn’t already have all the needed equipment to cast,size,lube,etc.
But if you want a 44 every Ruger and S&W revolver I’ve ever had were good accurate shooters. 44 caliber carbines are fun, I’ve had Marlin, Ruger, and Winchesters. Be aware that Marlins especially often have huge bores and can be difficult to get good results with cast bullets. H&R single shots used to be cheap and are easy to work with for cast bullet shooting. Your mold could work in a 444 as well if you can get it to cast large enough to properly fit the bore.
Lots of potential options just beware that you could get way down the rabbit hole really quickly.
