the reason a pipe needs to be chamfered is so it does not push the glue out as you are inserting the pipe
the proper way to insert your pipe into the fitting is twist it in, not push it in then twist
I usually hold a level on the middle socket, then push and twist the fitting onto the pipe
till i have it at the angle i desire
it is also a very good idea to ''ping'' or chamfer with a hammer, cast iron soil pipe
by ''pinging'' the pipe end you reduce the occurrence of the pipe binding up on the gasket and cutting it
gasketed sewer pipe must be chamfered if you do not want to fight with it. lol
i use a grinder to accomplish this