Best way to remove surface rust on sandblasted sheet metal

Here is where I found it beneficial to use Ospho. On pitted metal, unless I can sand it completely down the get rid of the pits. If I DA it and do not get rid of pits there will be rust in that small pit hole YES Soutern Urethanes said using Ospho ,water it down while wet. They caution the use of the Ospho. I have used the DuPont acid preps, worked great, but expensive like all pro auto paint products.I have always let the Ospho dry over nite clean, and use a DTM epoxy. I have never used Southern Urethanes product but I did order some of their epoxy, but have not chance a chance to use it yet.
I have used Ospho on countless cars for probably 7-8 years and only time I ever saw a reaction was where I simply applied Rustoleum directly over the bare metal cleaned with Ospho. No neutralizing. In a few spots the enamel wrinkled some I had a hard time DA ing that paint off with 80 grit! I always do filler over epoxy primer.
I bought a 6 cuda from a ar bud, the PO have DA ed it to bare metal , all of the CAR! Been sitting out side in the weather for 8 months when I traded for it. I DA ed it , wiped it down with the Ospho, only because it had me very minor pits, BUT pits. Used as usual TCP Global epoxy, sanding primer topcoats etc. I sold it 2 1/2 years later, NO issues. !!
I hav e been told by paint people smarter than me, IF the epoxy primers are acid base, that is when problems tend to arise if cleaning with Ospho.. There are probably more to this a chemist could explain.
I have no dog in this race, just discussing what I have experienced.