Fwiw some sources state that you dont want to amend the soil at all. Be aware that avocado trees are more sensitive to overwatering than other fruit trees. They do not like areas of the yard where the water table is high or there isbstanding water after it rains. Plant tree a couple inches above surrounding ground Brad

I don't know where you're located, but if it's at all hot, you might also consider rigging up a temporary shade structure over it, and mist the leaves frequently with a hose. If the leaves have really gotten damaged you may lose some or all of them, but don't give up on the tree if that happens. Chances are, it will still have enough energy to grow new leaves and recover.

Zone 7 is really pushing it for an olive tree.

have a soil test done.. and FIND OUT if you need to amend the soil for nutrients ... and after you have actual knowledge.. act accordingly ... IF there is any need at all ... in 99 % of situations.. we recommend avoiding adding much of anything to the planting hole ... unless the soil test indicates such.. and even then.. its usually NOT fertilizer [nitro] .... that can come later .. our usual goal at planting is getting over planting stresses ... when the tree is not hungry.. but stressed ... most profession field growers ... prefer clay soil ... it is not only usually nutrient rich ... but also .. when dealing with trees ... allows them to dig rootballs with soil attached.. so they can sell larger plants ball and burlap .... you are stuck on percentages .... of which... i dont see how you define or apply such ... practically speaking.. whats the effective difference between 30 or 40% sand??? .. and who is going to sell you such a highly defined soil ... except perhaps a snake oil salesman ....??? to help you understand ..... digging a hole in bad non draining clay.. and filling it with draining soil ... really gets you nowhere ... as the hole.. still doesnt drain ... so the usual idea.. is to plant high ... as you have noted ... and allow the tree .. to put its roots into the bad soil ... trees have evolved to do such ..... and are much better at it.. than we ever will be ... also understand.. that the root mass of a tree can end up.. two or 3 times the size of the tree you see above ground ... in a mostly pancake shaped form ... so it will quickly outgrow any raised bed you provide ... this happens in tree time ... so again ... what you are providing ... is a temporary setting.. so the tree can settle down.. and grow out of the stresses associated with planting ... you dont mention the size you are starting with ... smaller transplants get settled.. and start growing to norm faster than huge transplants.. because.. well done.. it can get over the stresses ... and get to work ... the answer you want .. has already been provided ... you need drainage ... at planting ... so the tree can get past the first year or two .. and then take care of itself ... also.. drainage can be manipulated.. by how you water ... e.g. if you are going to turn it into a bog by improper watering ... the type of soil you use.. isnt going to make much of a difference ... welcome to the forums.. see link below for general primer on planting trees ... a tree is a tree is a tree .. dont get to wrapped up in thinking each type has wildly different planting rules .. there may be some minor tweaks ... but all in all its all the same ... e.g. this MI boy has never grown an A outside of rooting a seed in a glass of water .. but ... imo ....my general trees guide.. stands ... the base bottom line.. plant it.. water it like a tree [sec 12 at link] ... and try not to love it to death.. and you ought to be well on your way .... gardening is more of an art.. than a science.. so dont get too wrapped up in numbers .... deal with the concepts ... welcome to the forums .... ken this guide used to have a section on planting in clay.. i dont know why brandon changed it at some point .... https://sites.google.com/site/tnarboretum/Home/planting-a-tree-or-shrub