I tried it but didn't have enough tension for my liking. I'm using two of the "original" springs like in this picture:
I noticed you slightly reamed out the bottom (skinnier) guide rod hole. I believe the flaw, as you state, was a wrongly canted hole? It binds a lot less than before. I have a drill press, i might just put on a felt polishing bit and polish the crap out of that tiny hole, if i can find one that small. Otherwise i think it will smooth out with usage, hopefully.
Looking at the picture if i push the end of the pump handle towards the barrel it works like butter. If there is any tension away from the barrel it binds, but a LOT less than before..
EDIT: punctuation fix.
EDIT2: i should rephrase that first sentence. With one spring it didn't have enough tension to send it back forward. With two it has enough for me to let go at the back of the stroke and it goes forward and locks by itself.