As far as avoiding the 3 hour test, there are some things you can do to sway the 1 hour test in your favor by minimizing and stabilizing your blood sugar before you do it. Basically try to schedule the test relatively early in the day, minimize your carbohydrate intake that morning and the night before (especially avoiding simple sugars and starches), and eat a some protein in the 2-3 hours before you go to the test. The process of digesting proteins can help.minimize how much your blood sugar spikes in response to the sugar load. None of this will "override" the test so that it looks negative if you have GD, but it can help prevent a false positive and maybe make you feel less sick during the test.
They never drew my blood when I went the first time bc I puked during the waiting time, but I hadn't done anything out of the ordinary to prepare. On my second try of the 1 hour test, I had grilled chicken and veggies with a piece of whole grain toast for dinner, got up around 6 am and had some almonds and a boiled egg for breakfast, and started the test around 730 or 800. The drink was still nasty and made me want to puke, but it wasn't the overwhelming full-body sickness I had the first time.