I made very similar build on Q76 with exact same Multistar setup than you and Sabvoton 72150, Cycle analyst etc. My build weight exactly 40.0kg (88 lbs).
I have Mxus v3 3000w on 24" 46mm wide DH rim with 12g spokes and Maxxis Holy Roller 24x2.4" weighting 11,5 kg (25lbs). That is about 4kg...