Good to hear that things are going better, Chris.
My wife has had success increasing her milk supply with Mother's Milk Tea, which was recommended to her by another breastfeeding mother.
Also the occassional O'Douls also helps increase her milk output.
We've got a grunty gassy baby too (although things have been better lately as we've worked out some of these strategies). Bicycling does help. We have some silly version called Booddle Heimer, but basically the same thing.
Tummy massages also help. Lightly circling your baby's gut in a clockwise direction.
My wife's aunt who is an emergency room nurse says mother's come in all the time with babies that are just gassy. They gel up a small hollow tube and insert in rectum. Poof, literally. Happy baby. (Don't know the exact procedure and materials, but I can ask if you want the details). A rectal thermometer can also be used in a pinch.
Babies need so much food and are growing so fast, their guts are never really in equilibrium for long.