i changed a condensor recently.
i was going to put on a 410a but when i looked in the indoor coil, the liquid line was only about 6" long on the inside and against the door , the suction was about 3" before it left the coil.
the copper (both) came out of the coil about 3" then a 90-degree drop downward.
the piston was in a fitting right at the coil sheet metal wall.
if i put in a txv it would have been right in front of the coil access.
i decided i might get myself into some trouble so i explained it to HO and slapped on an R22 condensor.
anyways, my question for you retrofit pros is, are you able to make the txv retrofit happen in any situation?