Sounds to me like you're doing the best thing - having it tested. I'd go from there. Wish I had some of your sand. Solid clay here in Justin.
J.D.

Most of us have alkaline soil here. You are right to add plenty of organic matter.

I used to think that the "compost" that I bought in bulk was not proper compost because it was not "finished" in my mind. But the thing is to add plenty of organic matter, and you'll be able to see it. Also add as much in the way of earthworm castings as you can manage.

Earthworms eat anything organic in the soil that isn't rock, basically, and they make loverly soil. Earthworm castings contain earthworm eggs and perhaps small earthworms. Medium finished compost provides earthworms with an ideal feeding ground. Mix the two together with some organic feed and either replace or amend your soil with it.

Please use Texas Plant and Soil Lab for soil testing. Probably the best one you can find.

I think I have a similar property like yours. Mine is nearby Richland Chamber reservoir lake (Corsicana) and I have Post Oak trees. Like you, I need a lot of organic matter. The ground underneath is bare which is NOT good for those oak trees. The previous owners probably didn't do a very good job.

It's probably too late to steal bags of leaves at this point. Look for tree services that trim branches off and put them through chipper. It's probably the best thing you can do. It will turn your soil to very nice stuff. They last a lot longer than expensive compost.

Here is a link that might be useful: Texas Plant and Soil Lab