any tips for influencing average surface cover estimates when creating biomes?

I created a few wasteland-style biomes. I want my volcanic wastelands to form in more mountainous locations. I would prefer sculk wastelands to form in plains or savanna wastelands and my fungal wastelands to form in swamp and jungle-type wastelands. I noticed that the volcanic wastelands do not show up often, and almost every beach is a sculk wasteland. The only biomes that spawn appropriately seem to be the fungal wasteland. I would like the biomes to be a little rarer because I intend to use them for some of the infection mods I use.