OH! I see where you're going with this. The fact that you're an engineer, (or claim to be), helps out quite a bit. You have the mentality and intelligence to understand that there's limitations in the equipment you're using. Even if you have four pieces of gear plugged into that, you won't be using all four at once, so over-amping the thing is a low probability.That I have a 14-30R at the back of my house prompted me to see what's available specifically to be able to use 120V tools with very little voltage drop vs. a 75' extension cord run from in the garage.
Run with it, and hope one of the molded-in conductors don't break in short order. (I HATE molded plugs.....it seems the conductor always breaks right at the plug.)
Roger