mixing promix with ground?

So at the end of last season I drove in a bunch of top soil and very old horse manure(4+ years old) to my location. when I first dug down the water table was at about 12" after spreading all the top soil and manure over the ground the water level was about 17". I know this wasn't a good idea leaving the soil naked all winter but its my first year doing a large grow so I didn't know better.
Ok so here is my idea. I was planning on digging down 24" tilling the original ground dirt and mixing all the stuff I had put on top. After that I want to build a raised bed of about 12" and fill it with pro mix. Now here is what I need help with, should i mix it all in with the bottom 24" or should i just lay it ontop of the 24" I had tilled, leaving me with.

Option 1:
12" of promix ontop, then 24" of tilled ground mixed with top soil and horse manure.

Oprion 2:
36" of mixed tilled ground, horse manure, top soil, and Promix.

Keep in mind this is my first large outdoor so any advice is great! thanks guys.

Hey, personally I love Pro-Mix cause its a great product. If your soil is already good...til it and mix it all together. I wouldnt leave the promix up top just in case the plant will favour it and limit the size of the root ball. I like to add 10% vermiculite for drainage and 10% perlite for aeration as well...works great. Peat also works great for its water retentive properties. Hope this helps...hit me up if there's anything else I can help with. Take care

Last season I used just the topsoil and horse manure mixed together in 2x3 holes. So im hoping for better results with the extra effort and products. Found a much better location, where i'm hoping I wont need to water because of the water table level. Where do I find lime to spread in the soil? can I use ground limestone, is it the same?

go to a home improvement store or nursery and ask where they stock the gardem lime.