I have a heavy wetter too. I just knit one-layer soakers and we haven't had any problems. I've considered adding a second panel in the wet zone (similar to an aristocrat), but it hasn't been necessary. My gauge is usually around 5.5 stitches/inch with worsted yarn from my local yarn shop, for comparison purposes. I don't see any reason why you couldn't use heavier wool - you might have to adjust your pattern, but other than that it should work fine.
