I am using an 1/8" piece of pyrex right now cut to size by a local glass shop. i also got some regular glass and plan to try various different configurations to see what works best with heat distribution and so forth.
the blower mod is from this thread:
3DP Part Cooling Fan 5015 Replacement - Snapmaker 2.0 - Snapmaker: where creation happens
theres various different designed mods and instructions for best results within the thread.
if you search for FiFix youll see how the calibration was done and i also posted some glass clips on that thread, but i think the print file is down right now because he is upgrading it.