[Squirrelloid]

P3G3L3Mg1 is my standard scales build, using temperature extreme of choice 3 to offset, and i've used everything from O3 to T3. I would definitely go scales on Jomon. Its worth noting that P and G are very good in CBM 1.9x.

Lord of Plenty or other gem-producing commanders are great for Jomon.

A pretender with specifically tailored magic to make use of key spells can also work.

Pure scales is perfectly playable for Jomon. (O3 and possibly taking Mg3 or dropping the temperature scale entirely).

I would not take a generic rainbow (you get plenty good magic diversity). I rarely take an awake SC (too much invested in the early game).