It won't cure either of your issues, the only noticeable difference of a worn ball is when you can select reverse without pushing down.
You'd be better off trying some different gear box oil, Redline MTL is recommended, but your box is obviously worn, so no amount of oil or bushes will make it better

As RJ said, remove the heat shield and spin it around the exhaust, disconnect the main shift rod to give you more room and you can remove it relatively easily.
The cheapest and easiest solution is to change your driving style, let the revs drop to idle before selecting reverse and don't plough in the power into 2nd.