More likely than you might think, though the specific "difficulty", for lack of a better word, would be getting the two to have either a substantial enough difference in height or endowment size to allow them to cock-fuck each other. By and large, Val and Brock tend to prefer being similarly sized, and when more extreme size differences happen (which is hardly a rare occurrence I should clarify), they will tend to engage first in more "regular" forms of sexual activity, using the disparate size to forgo the use of magic to make things "work" (e.g. not needing to dislocate a jaw like a snake would to give a blowjob to one of their hyper sized cocks)!
That said, the two are very regularly large enough to make a mess of a city (and then some), but they're also nice enough to clean up afterwards!

Hey there! Thank you for the compliment! I'm really glad you like my work!
Getting to your question, some of the themes you mentioned, specifically macro and some aspects of expansion (such as hyper growth, muscle growth, and macro growth) I am very much into!
Inflation on the other hand I'm not so much into, with a notable exception being cumflation, but that's more a byproduct of hyper than anything else.
Fat-furs by contrast, follow the same kind of thinking as a bunch of my other preferred content, which is to say I enjoy them in moderation or up to a certain size. Big soft women are great, but for me it really starts to lose it's appeal when it gets to the "blob" categories of sizes.
Now all that isn't to say that I'm against drawing that type of content, and to that point, I even have several characters specifically dedicated to be for inflation and fat-fur content should folks want to include my characters (or not have one of their own) when they want me to draw those themes. It's simply a matter of it not being content I actively seek out as it's not a major preference of mine!