The classes were fun! I choose to do unscented, uncolored, 100% CO with 20% SF via HP for several reasons:
1. We only had the room for several hours on a single day. That eliminated CP, which would have required them to transport sloshy, caustic soap batter from the site to their home. Going the HP route meant that the soap was zap-free and fairly firm when molded, making transportation from the site to their home much safer. However, if you have access to the studio on two separate days, CP is doable if you make a recipe that is relatively sure to firm up enough for unmolding by the time they return.
2. 100% CO HP soap traces, cooks, and firms up very quickly, especially in small batches. That mean less time stickblending and cooking. While we waited for it to firm up, we debriefed and reviewed proper soapmaking techniques. Some of them were able to cut the soaps before going home. Others were able to cut within a few hours after getting home.
For safety and ease of conducting the class, I chose to measure and mix all the students' lye solutions ahead of time. Dollar Store plastic cylinder containers with screw-on lids work perfectly for this. I did the same with the CO - I pre-measured it for each student into Dollar store rectangular containers with lids. Those containers then became their soap molds. They were ideal for a small batch that needs to be transported home.
This reduced the concerns for spills significantly because it allowed the students to observe while I measured and mixed my lye solution and CO. It streamlined the class process, too, which was important given the limited amount of time that we had to use the site. Yes, that meant that students didn't get hands-on experience with measuring and mixing lye solution, but it was a trade-off that worked best in my situation.
As for the blending and heating, be sure to test the studio's electrical capacity to have a lot of stickblenders and crockpots (or microwaves) going at one time without tripping the circuit breakers. This will dictate how many people can attend the class. Of course, to lessen the electrical load, half of the group could mix and cook while the other half watches, and then switch. That actually helps most people retain more information, because they get to both watch and do, but it does make the class twice as long.
Here is the list that I used to remind me what to bring:
GROUP SOAP-MAKING SUPPLY LIST
Recipe printout with cutting and storage instructions for each student to take home
Coconut oil
Lye
Distilled water
Gloves
Eye protection
Scale
Small container or cup for measuring dry lye
Cylindrical plastic containers with lids for measuring distilled water and mixing/storing lye solution.
Buckets or tubs for wash-up water (if no sink is available).
Rags or paper towels
Crockpots
Spatulas
Molds (rectangular or square containers with lids)
Freezer paper for lining molds and covering work surfaces
Scissors for cutting freezer paper
Masking tape for taping freezer paper on work surfaces
Pastry knife for cutting bars
Aprons