Just getting my head around PID variables. I'm curious in that all the IRL maps I've seen have an unreachable load request at low RPMs that would seem to be a factor in boost overshoot once actual nears request. Why would it not make sense to set lowest RPM load request values in IRL at closer to achievable targets in order to let PID do it's job with less tendency to overshoot?

Hahaha.

KFMIRL is not a boost request map.

LDRXN is more or like what you could look at.
It limits RL.
And usualy it has low and therefor reachable values for lower rpms.

But thats not all regarding boost and PID, just a startup hint.

Your goal is a proportional term of zero and your integral term should be just under your dimx at max load. Derivative term is pretty difficult to tune but is only active during rough correction. Increasing derivative will help a bit buy I'd sort out proportional and integral first. What's happening there is you're seeing  your max integral term based on dimx but it is being linearized to come up with wgdc. Sorry if you already knew all that though.