Typically I'll do a medium pizza when I get one. Mostly because nobody makes a large gluten free pizza. Also they're all square cut for some reason.

Most I've ever done was 36 slices at a Cici's Pizza buffet back in college. Lol, manager asked me to leave for eating too much.

Depends on how well controlled the diabetes is. With the right meds gaining is still an option, you just need to learn your limits.
For me personally I mostly need to watch my intake of added sugar. I handle natural sugar just fine, and as long as I keep my added sugar within the 100% of daily value and avoid caramel I'm good to go.

I'd say I'm mostly a 7.
I've not got the clothing extreme of a 7 but definitely have the stair issue of 8. So I'd say that fits.

Lol, I guess mine is actually the same. It fit fine in January. I've not had to use it since covid started and that was 65ish pounds ago.

Lol, I've definitely belly dialed people by accident when I've pulled out my hoodie and found it outgrown since last year.

So mathematically, if you're currently burning all the calories you eat, you should gain 21.5 pounds. I'm basing that on a 16oz jar.

Realistically it'll probably be more like 15, the human body isn't the most efficient machine. Couldn't really predict how you'll gain though, that's all down to genetics.

I don't think there is a set formula here. It's more to do with gaining quickly than with actual size. How well your skin stretches also is a factor. I've known ladies who reached 400 without them and a lady who gave herself a couple from a particularly large buffet trip.

Yeah, that method will definitely get you gaining.
Eating a little past where you feel full will slowly expand your capacity.
Anything you're eating above and beyond your calorie needs will eventually make you fatter. I knew someone who gained about 75 pounds on a vegan diet. You don't have to eat fast food or sweets to gain, but they're an easy source of calorie dense food.

I totally have that issue too. Eventually you can't spread anymore and it fills other space.

If you want to check your scale grab an unopened bag of sugar or flour and test it. They've got a known weight so results should match.

Some scales do allow adjustment, it's uncommon on digital scales but my mom's scale has it. If they have been adjusted it's usually to match the scale at their doctor's office scale.

Mechanical scales can also get off over time as springs wear or if they've been warped or bent. If grandma or someone in the family is near the limit that might have caused the discrepancy. I've personally caused that issue.

The other thing to check is that they're both on a hard, flat floor. If one is sitting on carpet you'll appear lighter.