Synthetic upholstery on furniture requires dying/painting with piping to be masked

I have 7 sofa/armchair cushions PVC/synthetic leather that are in white but I would like to dye them light grey leaving white piping around the edges. I've had a go at one but think it needs an expert to do a good job. I bought 5 cans of trg super colour spray 150ml in light grey but one can barely got through one cushion so 5 won't be enough. I'm based in east London so you must be able to come here and do the job. Will send pictures for those who are shortlisted for the job. Thanks