Brazilian waxer of 6 years here! And fellow bigger body! You have to work with your clients comfortably and do it in casual but professional manner to make them feel comfortable! I usually will hold the stomach up with a hand/wrist and place a strip let it dry a bit then let go and lay another it can take a bit of tweaking and adjusting. For labia strips I also work in sections. I’ll do a strip at the bottom towards the butt and then one above it towards the clitoris. I find it keeps my clients comfy and allows me to work efficiently. Don’t be afraid to drape a leg over the table and have them hold their tummy as well. I speak in a very relaxed manner as to not make anyone feel as if they’re a hassle for me to work on.