The way i do wheel changes is i find the picture that i want to take the wheels off and then i just cut round the actual wheel, some people like to have a bit of the tyre with the alloy but the problem with that is you see 2 different colours of tyre in the chop which you can see on your first posted pic of the MG.
Looks like your getting the hang of it now though, hope you find my advice helpful and good luck with your future chops etc