For me, since I have a couple of challenges enabled, the warrior seal, which can carry over a single +1 armor upgrade, as well as an enchantment once you get the talent, provide more consistent win rates for the warrior than the duelist. The extra armor especially helps in the early game.
Beating the game is not a sprint but a marathon that requires endurance. The best offense is a good defense and it's particularly true here. You're better off prioritizing having enough armor before you invest in your weapon. I play with reduced scrolls of upgrade but I'll prioritize having +7 scale or plate armor before DM-300. In some cases I'll spend a scroll or two on leather or scale armor to ensure I don't lose a run. That's at the cost of upgrading my weapon later. You can beat the game with a +2 or +3 weapon but it will be harder if you have poor armor.
The shops will always have at least one scroll of identify, remove curse, and magic map. If I don't have a stone of intuition on hand, I like to convert a scroll of identify to 2 intuition so I can find out which is the remove curse. If there's a few other scrolls at the shop, you can end up using more than one scroll's worth of intuition stones but generally you're conserving cost. I typically employ intuition for identitying which is a potion of strength and which are upgrade scrolls in the early game. As well as which potions are which for rooms that require specific ones. I generally try to use the stones sparingly as resources van be sparse in the early game.