>>8050991-Dissasembling the thing is easy with a hairdryer
-Removing the paint with alcohol or nail polish remover is easy, though it won't look like the untouched parts unless you can give it a soft, semi-glossy finish afterwards
-Cutting the piece with an x-acto knife is easy. Just look at other people's examples to have a reference for how much you want to cut. The issue with cutting too much is that it will look gappy at some point since the whole thing is designed with the flap in mind. The green piece also grows thicker the farther you go from the original edge.
I painted some cammo pattern on the modded section on mine, since I wasn't too happy with the different finish so I'd rather pretend it's a different piece of clothing altogether. I'm not concerned by accuracy to the original clothing. Good idea or bad idea, I guess your mileage may vary.