I always say that most SR guys actually earn about 50% nett of what they invoice, now this is a very rough guide. I have been out of the loop for a while but I think it must cost about £300 per week to have a decent SR van on the road before you start taking wages, unless of course you are part of a franchise and then it can be a lot more, please correct me if I am wrong.
They look good, what did you charge. Try spray out cards for masking they are a lot easier and quicker, failing that if you have broken the bead cling film also does the job quickly. If you really want to use masking tape and paper try spraying the tyre with a an aerosol adhesive first, even if the tyres have just been slicked the glue will stick and that tape also, both will come off easy with the paper when finished.