Scuba Tank Din Fitting Type? Will This Work

I have a Joe Brancato Great White CF tank but also have a steel 120 cu ft tank I can fill to 3500 psi. I presently use a an adapter and yoke fitting to fill. Even though in the picture the gauge appears clear I would like to use Joe's Din 300 scuba assembly for an easier to see and more accurate gauge. My question is I see there are Din 200 and Din 300 fittings. I believe the difference is the Din 300 is for higher pressure and the Din 200 for lower pressure. The Din 200 is shorter in thread length so it cannot make a seal and be used in a Din 300. I am not sure what size fitting is on my tank but can I use Joe's Din 300 assembly on my steel 120 tank. Bill
Scuba yoke hard to read for me probably not to accurate

My steel 120 scuba tank

Joe Brancato Din 300 scuba assembly