I'm hesitant to give blanket advice (I'm much more of a 'whatever works for you' kind of person), but with pizza, I would say no-one with T2 should be eating pizza. In fact I'd go as far to say that no-one with diabetes should be eating pizza full stop - and I say this as a big believer in the general principle that no food is off limits.
In my experience as a T1, pizza always contains more carbs that you think and you always eat more than you think. I used to get Papa John's pizza delivered from time to time and I would find that I would need to take the equivalent of three days' worth of bolus insulin and be injecting every hour just to keep my blood sugar under 20. I eventually narrowed down the problem. I simply didn't realise that a single slice of PJ pizza contains 40g of carbs. So two slices already is more carbs than a big bowl of pasta.
I find pizza very moreish and I can easily eat 5 or 6 slices without blinking - which of course means I'm actually eating 240g of carbs in one go. No wonder I was having trouble! More than that, once the pizza is 'in', it just seems to sit in my stomach for 8-10 hours spilling out glucose.
I suspect no-one can eat just one slice of pizza and if you're a T2, even 80g is probably pushing what your body can safely handle. As a result, I simply don't eat pizza anymore - it's too much hassle. KookyCat has the right strategy.