Canti post are mounted high for maximum leverage with 27s. (at least on my ’84) Wide 700s may work OK. but narrow 700 rims just don’t work with the brakes as the pads are moving more down than inward. Not completely accurate to say they “Don’t work.”, but not well enough for me.

OP,
Don’t worry about cornering clearance. As my son’s racing coach said, “If you are pedaling in corners you‘re going too damn slow.” I use MKS Grip Kings with pedal extenders. No problem.

Recently I was given (Yes, given!) a low mileage 21” 1984 Trek 720 Frame/Fork. Included were brakes, BB, Spidel headset and XT FD. The original owner, an old friend, hadn’t ridden it since being badly injured in a crash while touring England on it in 1989. BTW she had a pretty good idea what it was worth, having turned down several offers for it, but gave it to me to keep it “in the family”.

Love the bike with its long stays. Specially drawn for Trek by Reynolds, an inch longer than anyone else could buy. I tried to buy some from Trek, no luck. Ride quality is noticeably better than any of my other 531 framed bikes. I’m sure it also flexes more from pedaling forces. But I’m in agreement with Jan Heine that a certain amount of what he calls “planning” actually improves performance.

I’d often wondered why they were only made for 3 years. But the previous owner said it was a bit too flexible when carrying a lot of gear. Fortunately I have a couple of bikes with beefier frames for that sort of riding, so built it up as a comfortable "Day Tripper”. It’s interesting that the 728 came first. Was it intended as a serious tourer? Do they have low rider mounts? Seems the 720 should have been built with Reynolds Tourist weight tubes like my Jack Taylor. I've wanted a 720 since they 1st came out but I probably would have been happier with a 728 but hey, free bike, can’t be choosy. Single eyelets seem lame for a touring bike, my '77 Centurion ProTour had doubles.

Also tire clearance is marginal for modern touring rubber. She kept the wheels with their '80s 700-32 Specialized Touring II tires. They actually measured just over 25mm wide. My new 700-25 Michelins on another bike are actually a bit wider on similar rims.