When I got started in this trade the rule of thumb taught to me was yellow "wingnuts" was for 3 #12s and reds were for 5 #12s. Any combo that was close to that size.Mini's were for fl. lites ballast change out or in some fix it shop repairing old lamps.......
As for stab in splices it is about the same as backstabbing a recept. Its no good to get in that big of a hurry, never time to do it rite but time to come back and do it over.
Twisting wires that are the same guage is good but not twisting smaller guages to larger ones, the wirenut will do that for you---better.
Anyway I'm not doing that any more so no advice.
