You’ll have to excuse my ignorance on this subject, but I assume that the sealant will deal with thorn/glass type punctures on the fly?
General advice seems to be that two layers of tape will be needed for high pressures, I’m currently running about 40psi, but I’m needing to pump up to over 80psi go get the blighters to seat, would I need a double layer of tape? Sealant will seal small punctures, yes, but is also just a good idea in general – it seems to seat the tyres better and maintain a good bead / rim interface so they stay inflated over weeks.
I’ve never pumped a tubeless tyre up to 80 psi to seat it on a mountain bike, sounds way excessive and would have it flying off the rim on some designs. With proper tubeless ready stuff they should seat well below this.
Mad crazy pumpage is rarely required and when it is (typically with an older tyre with the bead a bit worn, or some rim / tyre combinations that are just bad) it’s at the initial inflation stage – once it’s going up above 20 psi or so you should be all set and it can inflate normally.