I have or have had gauntlets from RS, Man of War, Bobamaker and MF’s Fettpride set.
Bobamaker gauntlets are definitely the biggest. Then I’d say RS and Fettpride. Man of War for me were the tightest, but they can be heated up and shaped. I have medium sized forearms and for me the RS and Fettpride are a perfect fit.
For adjusting the fit on most make sure the bottom goes under/inside the top shell. Hinges are not recommended.