Well when you took the carb restrictor out it allowed more air to flow causing an overly lean condition which is more then likely why it wont start. Try and richening the LSN another 1/4 turn along with the HSN and see what that does. When you removed the carb restrictio it allows more air to flow so you have to let more fuel flow to the engine also, which means richening needles up a little bit. Try that and see what happens I belive that is what the problem is.

As for the ARO I just run my tank dry then add a 3 or 4 drop to the carb(when it's going to sit for more then 4 days) then turn the engine over and let it go after that. You dont have to go all crazy trying to get fuel away from the engine. Sometimes I dont even run the tank dry, I only use ARO when I know the truck will sit for more then 4 days, as rust does not form that quickly in these engine's. but using ARO after every run is good practice though.

But try what I said then get back to us on weather it worked or not.