I learned how to do high-temp fluid hot process from Ashley Greene's e-book on HP. It has a lot of great scientific info about how to formulate recipes, how to make the HP cook go faster, how to make the batter fluid for swirls, etc. You can get it on sale for about $25 through this weekend with the promo code SOAPLOVE.
https://www.ultimatehpsoap.com/hotprocess . It really upped my soap game and was worth the cost-savings bc I rarely have failed batches any more -- so no more wasted ingredients. Her liquid soap book is the only one I've seen that shows how to make liquid soap in 30 minutes, including dilution. The CP book is also good, but I haven't spent as much time with it, since HP and LS are my main jams.