What can I do to fix my blueberry raised garden soil mixture?

I have read in many places to do an equal mixture of sphagnum peat moss and of a good organic potting soil/mix for blueberries in a raised garden or in pots. So for my raised garden I need 8 cubic feet of S.P. moss and 8 cubic feet potting soil/mix. I put 6 cubic ft of S.P. moss in the box then started to add my bags of organic potting soil mix. I noticed that they had what looked like S.P. moss already in them so I checked the ingredients and sure enough it was in there(apparently potting "mix" and potting "soil" are different). I went ahead and added four 16quart bags of the potting mix to the peat which should give around the right amount of peat moss to the mix but since I wasn't aware that the mix had peat in it (and the garden center told me to use it) now I am not sure what to add for the other 8 cubic feet. If I add all the potting mix I am afraid it will be too acidic with all the peat. Should I add potting "soil" and just make sure there is no S.P. moss in it or can I add top soil and maybe mushroom compost(which I have a ton of now) and also if I can use the latter mix do I need to add a fertilizer to it?