Have an action on the way and getting ready to order my barrel from NSS, A Criterion sporter weight 26 inches long. Mostly it will be a coyote rifle with an occasional deer or antelope hunt thrown in. It will come in a 1-8 twist and I noticed this round seems to give higher velocities than the 243, even though it seems it would have a bit less case capacity. Will I need to use heavier bullets generally say 85 grains and up due to the faster speeds and twist? The Speer data lists 3350 to 3400fps with 90 gr. bullets. So I am trying to decide between ordering a bunch of 95 gr. Ballistic Tips hoping that at 3300 fps they will satisfactorily destroy coyotes and drop deer or should I stock up on 105 gr. Hornady BTHP's to shoot paper, coyotes and deer with? Will this bullet open fast enough to put coyotes down fast?
It sounds to me like you are making a mistake. I think you'll run into contradictory needs with varmint bullets, fast twist, high velocity, and coyotes vs antelope and deer. I think that is too many things to roll into one barrel and do any of them well. If you are not planning to shoot bullets over 105 grains the 1-8" twist is a mistake. If you are planning to go that heavy, then you'll need a longer throat which may not behave well with varmint bullets.
As I add up the factors you list, if it was me, I'd go with a 1-12" twist which will handle the 90 grain ballistic tip and accubond, plus 95 grain partition for antelope and deer, then for coyotes I'd look hard at the 70 grain ballistic tip .. the 65, 75, and 87 grain vmax and the 80 grain ballistic tip would be backup plans for coyotes.
... but that's me.
The fast twist is not going to work well with conventional varmint bullets .. Hornady SX, Speer TNT, Sierra Blitz. It might for a short while while the throat is smooth but after it gets a little rough, it'll start tearing the jackets and the bullets will start to tumble, maybe even come apart in flight. I've had that happen with several .22-250s, a couple .17s, and a .204 as they "aged." .243 / 6mm is not immune.