With a case length of only .050" longer and a shoulder angle .002" greater, I don't see any real advantages going to the 300 Dakota case. But. . .being as you have one, I would start at a mid-weight load for the 7mm Dakota and work your way up. I personally have wanted a 7mm Dakota for a while, but the brass availability has been my drawback. I do have a friend who I load for that has a 7mm Dakota (where my love of the cartridge came from) and a healthy dose of IMR 7828ssc or VV N560 are great powders with the 180 gr. Bergers in his rifle. He bought 500 pieces of brass with the rifle and he is set for a while. If I could ever find a stash of brass I'd build me a 7mm Dakota yesterday! IMO, I feel the 7mm Dakota is the perfect balance and case design in all of the Big 7mm's when slinging 175 gr.+ bullets. Good luck with your rifle.
I would think what works for the 28 Nosler would work well here as they are so close in capacity. The 7-300 Dakota was a case I looked at when the 7-300 WM became popular but instead shortened a 300 RUM and basically had a longer necked 28 Nosler, when a few months later they released the first Nosler, the 26. I stopped having a reamer made at that point.