gutairist has a 4x12 half stack marshall... house parties and local clubs venues
Your Behringer would probably have been ok for these gigs, maybe even adequate. 250W out of the Rumble and that cab should be more than enough, not quite to say 'you are bringing too much amp to the gig,' but I doubt you'd be going over half on your volume ever in those size rooms.
It will be plenty loud unless the guitar player likes to dime the Marshall. Basically when competing with tube guitar stacks there is no such thing as the bass being loud enough
This right here is what you should be paying attention to.
A 30W 212 guitar amp would probably be plenty loud for those gigs. Just so you know. What's the actual amp head? How high up is its volume? If you stand in the very back of the place can you clearly hear every drum beat over the guitar? Even with a half stack, 100W is enough for an outdoor stage, very large concert hall, etc. For reference, the 50W 5150 III (based on Marshall designs by way of Peavey and now Ed's own company) is described thusly;
the EVH 5150III 50W ... is the perfect amp for players who want arena volume and performance in a compact package.
50W guitar head is 'arena volume' (according to marketing hype, but this is just to illustrate the point). Yes speaker area, ohms, and efficiency all matters just like it does for you. But while they need 50W for 'arena volume' you are asking if 250W is enough. Those two wattages, if they are both tube amps and 'equivalent' cabs (half stack = 810, 215, 218, or 412 for you) are approximately equal. With the rumble into 8 ohms you are about 2/3 or 3/4 'equivalent' power if they are running 50W tube head, and severely outgunned if they run 100W tube head.
Other than vocals what's going into the PA? Your volume
should be more dependent on whether drums/which drums are in the PA than the guitar amp in those size venues; ie not being drowned out by toms or kick. Even for hard rock and hardcore, it's likely too much guitar amp for the stage.