Remember with rads & condensers it's
air flow not static amount which matters.
As such, "restricted" flow amount will be much lower than 23% (with 77% "open" mesh).
After losing a condenser on each side of my 997 (one from a stone and other a prehistoric sized bee w perfect aim
) I fabbed some mesh grilles. Ran w them for 7+ years including plenty of extended track time w upper 90's temps. Cooling was never an issue. Note all modern GT series cars (at least since 991.1) have factory mesh.
The little junk - sand, etc. will always get thru - it's just part of the program and good reason to make cleaning your rads at least every other year part of regular maintenance.
YMMV - good luck
