I will be ordering a 26" barrel and will shoot mainly 130-150 grain bullets. I think a 1-10 would be best, any insight from those who have shot down this road?

If you plan on shooting some of the Ballistic Tip or Barnes TSX bullets that are long compared to cup and core bullets you might be dissappointed with a 1 in 10 twist. A 1 in 8.5 will work with any hunting bullet you will be able to try. A 150gr TSX is as long as a 175gr conventional bullet and will need the extra twist. It will still shoot light or short bullets well too. Would hate to see someone spend the money on a custom barrel or rifle and be unhappy with it when it could be prevented.

I have three rifles chambered to the 7x57 Mauser. All three have 1 in 10" twists and stabilize the 140 gr. Nosler BT just fine. In fact, with one exception, my Model 70 Feather weight will shoot groups ranging from .375" to just a hair under one inch with everything I've run through it from 120 gr. Nosler BTs to the 175 gr. Hornady round nose. I haven't tried the 175 gr. Spitzers yet, but I'll get around to it one of these days. The only bullet that does not shoot worth a damn is the Winchester 150 gr. Power Point bullet. I weighed a bunch of them and they weighed plus or minus 2 full grains from the stated 150 grain weight. (148 gr. to 152 gr.) Pure garbage.
I think my ruger #1 in 7x57 is also 1 in 10" but it might be 1 in 9.5". My FN mauser with a top of the line Douglas barrel is also 1 in 10", but the only thing I've run through it so far is the Winchester factory 145 gr. load which goes into nice tight groups.
Based on those trhree rifles, I don't see a problem with most bullets including at least the 175 gr. RN. I won't comment on the spitzers till I get a chance to try them.
Paul B.

Personally I'd be looking to a 1-9" twist as it will do the 130-150 grainers but the longer ones too.