So first thing, i'm not a big fan of [Mesa's Waltz], i get why people like it, use it if you want to ;)

You may ask why so low STR since it increases Regulator DMG:
Answer simple they dont need more and you max out at 155% for your Shatter Shield DMG reduction.

Range doesn't affect your [Regulators] Range doesn't affect your [Regulators] Build

Fleeting & [Streamline] not maxed?
Yes not everyone know but, Efficiency is capped at 175% so in having a 2nd Fleeting & [Streamline] each Rank 4 means less drain ;)

WARNING:
As always Aracanes only enhance the build, they are not needed to play it ;)
Same goes for Exilus, Enhances gameplay but not needed.