Best image projection workflow

Hey guys,

about 2 year ago I used Substance Painter as my main Texturing Tool. But when I started to do very big assets with lots of UDIMs, I switched to Mari, since it was much easier to work in such Projects there. In the last 2 years though, SP added lots of new stuff (especially better UDIM support), so I’m thinking of using it a more again.

1. In Mari, I often paint stuff like rust leaks by hand, since I need them in very specific areas (like on vents etc.) After I have painted them, I then can just use an HSV and Levels node, to get and adjust my Roughness and Height map from it. The problem is, I have not yet found out how to go about that in SP. I watched some tutorials on the image project tools, but they only show how to paint on the color channel. What is the Workflow on creating bumb and roughness maps from that? I cant really create them before hand in Photoshop, since I often use many different images for that, and that would take forever to do that.

2. I’ve seen some Videos on SP, and most people import premade PBR materials from e.g. megascans etc., and others create the supporting maps (roughness, bumb etc.) in Photoshop beforehand.
My question is: Is there also a way to do that in SP itself? I often use normal photo textures, and experiment a lot with them, until I find something I like. Always exporting the supporting maps from photoshop seems very time consuming, just for quickly testing stuff.

These are 2 things that I really like about Mari, and that have prevented me from returning to SP.
What is your workflow on that?