I run 2 BenQ 2150STs. Nothing grainy and Gamma is fine at the Blend, I think the darker screen is helping there. Only thing I don’t like about two is any bump of the projectors screw up the alignment which is very noticeable when the line is directly in front of you. Three PJ s is much better in that respect.
I may set mine back up, but I’m enjoying my 55’’ 4K at the moment. May have to upgrade my projectors.