I have a 260 Rem with 28" Border cut 5R tube on it - bloody big and heavy 1.25" tube no taper. It shoots very well, it also shot very well from the first shots very little load development and cleans easy. I can take off-hand shots but it is not really pleasant for long.
BUT...if you are using it as a field gun something shorter and lighter...max 26" and may be 24" better. If you had a full cylinder from the brech for 4" or 5" then a taper down to about .930" at the muzzle you could re-chamber later (more barrel life for your money). Not sure if you are using a break or can but a 3/4" thread (not smaller is a good idea).
Maker....you might well get more barrel life out of a Lothar Walther...harder steel. I would not sweat cut or buttoned (says me who had to have cut rifled barrel before), more likely to be screwed up by the plumber...cutting a good chamber is a big thing. I am biased but I am going to try a Lothar Walther on the next project and Pete is doing the plumbing.
Really I know too many people / gun plumbers who say cut vs buttoned not much in it - ask Derek I think he has a tack driver Lothar Walther on his 6mmBr belly benchrester and Pete was the plumber.
Worth thinking about flutes?...cost about 100 quid, not bad on a 308 (5K barrel life) but on 243 Win 1200 - 1500 rounds barell life....expensive.
If you want something other than 243 Win.....6.5x47 Lapua is looking very nice...easier than .260Rem for the same performance and Pete (that man again) is getting a reamer in.
As an option the last time i checked RPA had some Krieger cut rifled barrels in (one is on a mates
. If I could choose a barrel I would buy krieger but here LW and Border are easier options.
Hope it helps,