Wow, what a great job man! Question: how did you make sure you didnít touch the black leather with the yellow paint? Iím curious...
So it seemed daunting at first potentially ruining an expensive new suit. It didnt help that painter's tape wasn't sticking to the leather so there was no choice but to free hand it. You'll see that i used a brush with a fine point. That was the only brush I used for the entire suit, mainly to control how much paint gets on the leather, especially on the perforated areas. You can feel free to use the wider brushes if you feel you have the control. For the edges, it was a mixture of going slow and also using my other hand to pull back the leather so the brush can get into the edge better. There were several times a touch of paint got on the black leather but a quick finger swipe will remove it no problem. I did the job over the course of 3 days. Each day, I gained better control of using the brush.
If you do this, you definitely want to use that Preparer bottle so you provide a good clean surface for the paint to stick to. But be very careful with it. My advice is to do 4 or 5 very light passes on the leather. Don't rub the leather back and forth like you're trying to wash it. The stuff is basically acetone and it will start to pull the original paint under in an ugly fashion. The paint that is pulled off starts to clump up and it gets messy and very very difficult to clean up. This is what I discovered on the first section I did. So what I advise is to get a paper towel, rip up small 1 inch squares of paper, apply the Preparer on the paper, and very accurately apply it to only the leather you intend to paint. If it's a section of leather that will not be painted, don't let the liquid touch it.
Painting: I advise ~3-4 light coats to get a full deep coat. Wait 20-30 mins between coats. Clean off the brush of any dried up paint between coats so you're restarting with a fresh brush.
Matte Acrylic: Use a new brush for this. This stuff is very viscous - like water. One coat seems sufficient. I also advise painting this on accurately. Even though it's matte, the tiny slivers of black leather that it got on now has a slight sheen to it. You'd only notice it if you looked for it, but otherwise I think the suit came out 98/100.
Take your sweet sweet time with a steady hand, and it'll come out right.