By far easier if you want to stay under 2 bar boost is to just fit 3 bar pressure sensor and underscale everything by 20%. Works reasonably well.
I have been searching about this topic, and at the same task (stay under 2 bar boost), when you say (just fit 3 bar pressure sensor and underscale everything by 20%), do you mean use a 3bar MAP sensor with 2.5bar DSVDGRAD / DSVDOFS values? and underscale by 20% every requested/actual boost axis & maps?