Sjtaylor

I recently purchased a 2003 Leland Buenos Aries. It has Bontrager Select wheels, the stock ones I think. It has 700c-23 tires. I’m focusing on fitness and making miles rather than racing and I plan to sign up for a couple of upcoming group fun metric half century rides. How large a tire can run and how large a tire should I run? The frame is 61cm and I’m 6’3”, 225lbs.

Thanks.