Burning tongue is a known low estrogen problem.
The thing is, they can create these lovely tables showing us what the equivalent doses are - but since we tend to absorb these things differently, it's all a bit arbitrary really. Like I get much more estrogen from 3 pumps of gel than from a 75 patch. So really... pick the method of administration you like, gradually increase until symptoms go. If you get to the max licenced dose and symptoms still haven't gone (that's 4 pumps of gel or 100 patch) then have bloods done and if they come back low, you can go higher... But switching from one thing to another can mean starting the figuring-out-the-dose thing from scratch because we absorb different products differently.