I don't want to argue for sure, but I also am not trying to find a loophole.
In my particular case, my goal is to start research in the next year or two. I am not comfortable with making my own grains due to my living situation and logical safety concerns. I am most interested in core geometry (38mm-54mm, nothing huge) and doing stuff repeatably, which the RCS stuff seems to be ideal for. Someday, I'd like to try doing my own chemistry, but that has to be years away for me.
Having said that, I still don't understand if buying a bag of parts (based on running sims myself and specified by me) from RCS vs. CTI (or AMW, Gorilla, Estes, Loki or other - I know some are no longer around) would be acceptable to launch at a generic TRA launch. I like the idea of trying the RCS options for sure, but if I could buy either from a known manufacturer or a buddy on the field would be good to understand very clearly before trying to figure out what road to follow.
At the end of the day, I really want to do hybrids, but I think learning about each option is important. While plenty of people probably know the right answer, for me it is true research to learn it for yourself with your own effort. I think learning about solids will be easier due to user base, as it seems that hybrids are 1/100 of the flights. Do you have to know everything about solids to try hybrids - I assume no, but why not become educated about everything you can before trying something new.
Sandy.