well ,here goes if i was gonna go the way you want,it would be just ocean forest,now you have a big clay base,takes time to resolve this issue,but you can break your clay up with gypsum,if your going the ocean forest route,just dig your hole bigger than planned and get some gypsum in that soil to start breaking up,in the past i mixed sheetrock busted all up and sand to help along the way,.
here is a tip that could save you money,take a 1 quart size mason jar,put 1 cup of water in it,then put 2tbsp of calgon or ivory soap, then 1 cup of the soil from your hole,shake that fucker to no end ,after a couple minutes,and completly shook up,place the jar on a even surface and let it sit undesturbed for 24 hrs,this is the out come of test,all your sand will sink to the bottom,then your clay,then silt.
what you are looking for is a even balance of all three,there will be no problem identifying these levels because colors are diffrent,all your compost,coco perlite all your air amends will float to the top,then water then the three we are talking about,if it turns out they are all equal then you can just add your disired amends and air products,growing organic,is about keeping your soil alive and not killing all your bennies and bioligy,all that comes into play after you get your soil right.now if you want to save money on amends ,just go to kelp4less.com and look at the soil cutter starter,has everything in 1 package and doesnt need reamended for at the least 2 yrs,depends on your feeding methods,its cheaper this route or was for me,,you mix this stuff with any garden soil or soil,a entry level box of 10 lbs does 5 cu ft,so your 30 ft hole would just about be perfect,hope you understand all this ,its easy as hell will show you exactually what your soil needs for the equal amount of a perfect base,and if you decide you want to purchase the soil cutter,enter oldskol4evr in coupon box for 15% off