Prefectly happy to show anyone how an effect was achieved, the biggest problem one finds even with SBS explanations is that lighting and video effects do not often show clearly how something was done.
One has seen loads of publications with some very thorough explanations including plenty of photo's that still left one none the wiser as to how it was achieved (how to do glazes on figure painting with acrylics still leaves me stumped until a very experienced figure painter said "can you do blends with oils ?" I said yes and he curtly replied "Use oils then".)
As for dry brushing - well lets take an instrument panel as an example.
Most (but not all ) we shall assume will be black - so lets paint it good old NATO black which is in fact very dark grey or "scale black".
Select a slightly lighter colour and using a largish flat brush , scrub off virtually all the paint on a paper towel until there is virtually no paint left (test on a bit of scrap). Flick the end of the bristles over the raised detail, stop and check to see the effect. Stop when it looks good to you.
That last bit was the rub - stop when you find it pleasing.
The top modellers are perfectionists (this one isn't) so will redo something over and over again until it is perfect - very admirable and the results speak for themselves. This one is a realist so good enough will do.
The new tool Gnat build in the Airfix magazine left me a bit cold - assuming we are talking natural metal/Orange.
Those slightly overscale panel lines seemed to be an open invite for a wash.
Looks fine if subtle enough and overblown if not.
Having a look at photo's of a real one - not a panel line in sight, so how to make a smale object look less boring or toy like ?
Well one way is very laborious and is to mask off all the NM panels and slightly vary the tone of Ally paint used - results in a patchwork that looks a lot more interesting and realistic - a spot of post shading on the orange bits (slightly darker shade of Orange sprayed near the panel lines) livened up that part.
But as far as one is concerned, if your happy with what you have done , then that's just fine, the point is give techniques a go on old kits, if it works or you like it then have a go on something more meaningful. Practice is everything.
As for figure and bust painting - check out the work of Sang Eon Lee - simply stunning. After thrirty years on and off of trying to get anywhere near the quality of such painters , maybe half way, know all the techniques, yet lack that one thing he has - talent. It wont stop me trying though.