I have the 2.5 Moto fab top mount spacer on my 2020 Sierra crew cab. I originally installed the Rough Country bottom mount spacer but removed it and installed the Moto fab due to clearance between the CV boot & the strut bolt. Only issue I had was when you mount the spacer to the strut you have to rotate the strut 180 degrees when reinstalling. This causes the tabs that mount the strut to the control arm are angled in the opposite direction making it impossible to thread the bolts in. I took a large adjustable and rotated the tabs to match the angle of the control arm. I saw where the Rough Country top mount spacer disassembles the strut and rotates it 180 degrees. (Check their website) Looks to correct the angle of the tabs when reinstalling the strut. As far as the height, I installed the rear factory spring blocks that I removed from my 2014 Sierra and have about a 1 inch rake. You might want to add a 1 inch block to the rear...
Hope this helps!