Would this have any shot of working or am I wildly off base?
No matter what, something like this can't be added without having to check/update every single scene it could affect. The two main problems are: 1. There's no way for the game to tell that a sex scene is taking place, since they're coded in the exact same way as regular scenes, and 2. An NPC's orifice capacities are tied to their statblock, which has to be called manually every single time they're used.
The only way I can think of to bypass these problems is to put it into the cockThatFits() function (which has orifice capacity as a required argument, and is what normally gates those scenes) - but that function is called while the sex menu is being generated, so I can't think of a way to implement it without resulting in cock shrinkage every time that function is called - which means your cock would always shrink to the appropriate size even if you don't pick the relevant scene (which, as a side effect, would permanently lock out hyper scenes that use cockThatFits as their check). Even if that weren't an issue, some scenes use other functions like biggestCockVolume() (which
doesn't accept orifice capacity as an argument), so it wouldn't cover everything.
Actually, I can think of another way to bypass it: add an always-accessible option in the side menu that applies Condensol if you have at least one in your inventory (and possibly also has a restriction preventing overdosing), then refreshes the current menu. I'm not sure if that would work, though: I don't know the code at that high of a level.