Unless you have to remove the bevel box for another reason, doing the seal replacement in situ is the better option. If you remove the BB you are doing a lot of unnecessary work for no gain. If you are paying a mechanic by the hour, then you are increasing the cost for nothing.
Adjusting the rear wheel alignment and belt tension (an article about doing this on the MTWC website links dated Jan 2018) doesn't reduce the amount of work to remove the BB much. Cutting and then bolting a plate over the brackets is a useful modification to do any way, it makes any future work on the propshaft easier.
