Had to make one like that to save a local curry restaurants stock. Had a leak i couldn't find at first so put some dye in.... Everything glowed green dye to food colouring!!! Then a month later found capilary snapped of exit of distributor. Made new distributor out of squashed 1/2", just make sure to have it level to even up the flow as best as possible.
Several times I have seen a home-made distributor nozzle that was favoring one tube over the others. The first one I saw that had an issue, was on a walk-in-cooler and it was freezing up one circuit of the evaporator, and the other two circuits weren't doing anything. I used a pinch off-tool to restrict the flow in the favored one as a last ditch effort, and it worked! All three circuits starting frosting up evenly. I couldn't believe it, but it has been like that for about a year and no other issues. (But of course, your issue of heavy frost on TXV sounds like a different issue altogether.)