I swapped out the St Germain for Domaine de Canton ginger liqueur and think I prefer it. It's already so busy flavour wise that I think the ginger helps calm it down a bit.

The play between the earthy mezcal and the Earl Grey is perfection. I just made a batch of really strong Earl Grey and added that in rather than making the infusion and it tasted great to me. Dried chilli flakes also worked as a replacement for fresh. While I understand the other comments about using lime instead of lemon it's the lemon here that elevates things for me. Every other tequila / mezcal drink is made using lime so it's a nice surprise here to have something different.