I own and wear the 997, and I have occasional, severe digestive issues as a symptom of another chronic illness. You probably won't want to hear this, but when I'm having flare ups, I generally don't bind. I have fibromyalgia, so any little bit of comfort or reduction of stress on my body when I'm flaring up makes a lot of difference. Of course, I'm also lucky enough to have an understanding boss and the ability to work from home if need be.
When I have to go out, I use less restrictive concealing methods. Find a few sports bras that are a size down from what you usually wear. Put on one that fits first, then put the tighter one over top. This should help reduce the size of your chest while also reducing the amount of discomfort from the tighter bra cutting into you.
Apart from that, layering! This is good because it doesn't make you uncomfortable at all - the only downside being that if you get hot you might have to suffer through it. Start with your underwear, socks, pants, etc. Put on a tanktop and tuck it in so it's tight. If it's cold, put on thin long sleeve shirt and do the same. Then a t-shirt or sweater, then a hoodie. I'm a small dude (5'4"), but I've found that if I dress in certain ways (even without binding sometimes!), I manage to pass.