I think I'm going to wait until I've got the engine reassembled before I burn the mounts in anyhow so I've got time to mess with it.
Catching up on the forum after being away on work travel. Very glad to see this comment as I was hoping you'd come this conclusion as I was reading your posts for the week.
Based off @NashvilleTJ 's comment on checking clearance at the firewall with the heads & valve cover had me concerned of you burning them in now and needing to remove the mounts or modify the firewall once the heads are on...
I've never done a engine job like this with new mounts but I'm hoping you stay in the 'wait until engine is together' camp so Murphy doesn't get you...