Just wondering is there a way I can simply edit the effect of a filter?

IE: Like the intensity of "pressed steel" so I can get just the right amount of change?

Yes, in version 0.47, we have the Filter Editor in the Filter menu. I've just dived into it recently, and find only precious little instruction. So it's a big trial and error effort for me. Not that that's a bad thing -- it is fun learning, or trying to

There is a relatively detailed chapter in the tavmjong bah Guide (see link in my signature). So it's a good start with the very basics, but still I find myself stumbling along. Anyway, what I'm trying to say is that yes, you can do what you want, but no, I can't instruct you exactly how to do it. Sorry, I wish I could be more help.

I followed the tutorials here when learning. It's hard to give specific advice.

Oh wow, Slow Dog. That looks great, thanks for sharing!