I use plain base gas checks on the 9mm. I had fits with my brothers 9mm and tried everything I could think of to make it shoot good without leading the barrel. No luck until I got these checks and now its completly lead free and accurate even with hot loads.
I'm using air cooled WW with a hardness of around 12-15 according to my Lee tester. I dont know if water dropping pure lead bullets does anything lasting, but water dropping WW or WW/pure lead bullets does make them harder. I get around 21-23 with WW and 15-17 with WW/pure lead/tin (50/50/2%).
The bullets will get a little harder over time, thats why I put the spreads in the numbers. You can add more or less tin or add more antimony from lead shot to tweek if you want. I keep mine simple for remelting my reclaimed bullets. I use plain WW for general shooting and varmints, and 50/50/2% either water dropped or heat treated and anneal the nose for hunting purposes.
The key to water dropping is to keep a consistant count when your making them. I usually knock the sprue cutter on count 20 and drop them in a 5 gal bucket of water. I'll make probly 40 bullets getting everthing to a constant temp and get my count figured out before I knock them in the bucket. Then, about every 20 I'll knock out a pair on my towel to check and make sure everything is still good. Thats my
Opinions and methods vary and this is just what I do. It works good for me. The nice thing about casting is you can make them however you want.