As with all these carry-on discussion, YMMV depending on the gate agents. The few times I've flown WizzAir, gate staff used the (hard) luggage sizer AND a hand-scale to weigh each carry-on. Most issues were about the weight and anybody with more than 10kg was forced to check & pay.
I wouldn't risk any hard-sided carry-on that's too big or anything overweighed, not worth the hassle at the gate...
Related to this, I was just forced to buy a WizzAir ticket (they were the only carrier with the workable route/timing). My carry on bag is the correct size dimension but it likely will be overweight. I purchased both the Wizz Priority boarding/carry on bag option AND the checked bag option (not to mention the airport check-in option). I really don't want to check in my bag simply for the convenience.
If I show up at the gate and they decided to weigh the bag, determine that it's overweight and demand that I check it in, will they charge me a checked-bag fee there even if I already paid a checked bag fee?