I definitely agree with Ian, unless they are very shallow no client is going to be put off by you having a realistic figure for your age and parental status!
I do empathise because I was very self conscious about various wobbly bits when I started but I soon realised the vast majority of men couldn't give a flying fuck as long as you're giving a good service. And body confidence is really sexy!
For now, why not look for a deep suspender belt set? They're very good at hiding stretchmarks and wobbly bits in that area.
I would also suggest changing your marketing angle and branding yourself as a MILF. Most guys realise that mums don't have perfectly toned abs because, duh, you grew another human inside you!
BTW I am a size 14-16, I have loose skin on my belly, my thighs are enormous and I have bingo wings. Today I'd seen 5 clients by 1.30pm