How much Sphagnum Peat Moss?

So I was going to make a soil less mix out of sphagnum peat moss and river stone. My idea was to layer the sphagnum peat moss in between layers of river stone and have a thick layer of the peat moss on the bottom. The peat moss retains up to twenty times its weight in water so I figure even though the stone will dry out fast the peat moss will retain enough moisture for the roots. Anyway, the stone has a ph of 7.0 and the peat moss can be quite acidic, I've read even as low as 3.5. Can anyone tell me what ratio I should use in my mix to achieve a slightly acidic ph? I'm using organic fertilizers which can also be acidic so I want to make sure not to over do it on the peat moss.

Bump..........

Seriously, no one knows the right ratio?

iono make your soil, test the soils's pH then add lime accordingly, peat is kinda a bitch i found i always had pH problems come flower time as flower nutes have an acidic pH so combined with the peat i had issues, not to say they couldn't be fixed just a pain. i would look into growing organically with super soils, i switched to that method and haven't looked back adn the plants freakin love it

perlite retains alot of moisture too and adds to soil aeration

Actually perlite is what I was originally looking for. I was shocked when I couldn't find it in town. I was going for mostly perlite and some sphagnum peat for water retention. Then use a full spectrum organic hydro nutrient.
I found the river stones and figured it really doesn't matter what type of stone or material you use, as long as it provides aeration for the roots, retains some moisture, and is inert and non metallic. So I picked up the stone, but I have no idea how much sphagnum peat to use without making the mix too acidic. Anyone????

old thread but i was looking for this answer and couldn't find it. my soil was 7.0 when i tested it i added 25% peat moss to 75% soil (as i said was 7.0) and i got a reading of 6.5
if your not dealing with those numbers, i think it could give you an educated guess.