Edge Highlights on Vehicles

Greetings True Kin, I seek advice! My Kabal colors are Nagarroth Night with edge highlights of Xereus Purple and Moot Green, which look great together, but I have a problem. My after a few years in the Army my hands have the shakes. My edge highlights are not particularly straigh, and vary in thickness along the line. On random Kabalites that don't really get looked at it isn't particularly noticable, but on my Razorwing it definitely is. I have the outer edges done in Xereus, and the lines separating sections done in Moot which looks great from a few feet away, but the lines are choppy and jagged close up. Any advice on highlighting vehicles would be much appreciated.

Drybrush... a really really dry brush with very soft hair. Applied not across the edge but the stroke needs to be along the edge and made by the side of the bristles. Few layers each.

Yeah, I have this issue too. I just use very little paint and use the side of the brush wherever I can, going over the same lines many times over.

Paint scotch (or selective varnish but in this particular case this won't help much).

Apply schotch as neat as you can were the highlight should stop (you can even reposition it).
Add highlights. Remove scotch with excess paint.

Won't be ideal but you loose less time reposition the scotch rather than correcting highlights.
Prefer drybrush in order to avoid scotch soaking the paint.

Hope it'll helps :/

Ps : Another option is to ask someone to make your highlights ; in exchange you can undercoat theirs/basecoat/wtv....