Those Kenda Kwick look like they might be worth a look. An amazon Q & A said they measured them at 27.5 (Didn't say what size rim). Not too expensive either.
I'm 5,9" 160 lbs, so while I"m not overweight, I'm not exactly a standard cyclists build either.
I have taken my road bike down a few gravel roads with 25mm tires, and the results were less than confidence inspiring.