+1 The only reason to cut the steerer is for an entirely new setup/bike or because you absolutely have to get the bars lower. (Race fit in the days before all the stem choices and you did not know/could not afford a framebuilder to make you a <-17 degree custom stem.)

My custom fix gear (my avatar photo) came with a moderately low stack King Gripnut. That headset drove me nuts and I rebuilt it with a collection of Tange parts to get the good races and low enough stack. Worked but every 8000 miles I had to collect the various parts to re-do it. Finally had the builder shave some off the head tube. (Thankfully, he left enough there when he built the frame to make that possible.) Now a standard Levin drops in. Bliss!

The aside - I absolutely love that Tange makes all its headsets interchangeable. Diameters, lockwashers and locknuts. With enough old ones on hand, you can come up with parts to fit almost anything. You don't have to take out loans to buy them. Even the cheapest headsets, the no-name OEM ones bike shops use to keep beaters going install just fine and feel smooth. Look decent. Last a good long time (except they do not have seals. You have to keep grit out - inner tube seal or gobs of marine grease. But for $8 pre-COVID, who's complaining. And they can be used to shrink stack on all the other models.)

Edit: Just read the above post. Never thought about it but in general, I don't mix and match cups and cones so I haven't run into seal issues. But if it were necessary, I'd just do it and pack with tons of marine grease; enough to ooze out and require a post first ride wipe.