one thing I meant to add as it relates to your first question - it's tough for someone to come say 'oh this location will max out 12ft' because there are general sizes but there are ALWAYS exceptions to the rule
super dwarf localities that have the most potential for staying small would be Karompa (don't think you can find any), Madu (also none for sale, long wait list) and then Kalatoa, these are the truest super dwarf localities. Mostly you will find % mixes. Jampea and Selayar Islands are dwarfs and Kayuadi are generally on the edge of super dwarf. Please keep in mind dwarf and super dwarf are general descriptive terms created to get an idea of potential sizes.