I was researching rootstocks a couple of years ago, mostly apples; but then also got distracted into other fruit trees also! Mostly I was planning on grafting about 10 apple trees, but wanted a peach or two also - and though I bought a Marianna 26-24 from HOS, was surprised that they were offering it for use with peach; all the information I'd found on it showed it "For apricots, plums, most almonds.", no mention of peaches. Though also said to be more tolerant of wet soils than Lovell, which is a peach! So kind of confusing, and I didn't feel like experimenting by trying to graft a peach onto it and having it fail years later - I grafted a plum onto it. So again, no hard answer; but I choose not to use it for peach since I could find no mention of it being used for peach anywhere on the web!
Dave

I don't know enough to judge if this info is right. But see the first paragraph of p. 23 of http://www.nyshs.org/fq/05wint.....winter.pdf.