Thats a lovely coach youve got there. I am currently practicing lining on a ratio 4 wheeler. The results are not pretty lol but I would dearly love to develop the skill of bow-pen lining. Though I have tried on the ratio kit, I've found that I can draw a finer line with a brush... but the problem is consistency - I can not draw a consistently fine, straight line with a brush. Anyway, once Id done that, I tried to draw pen lines on and they looked terrible - even though they were straight and consistent, they were far too wide and spoiled the whole look.
I think youve done yourself proud so far, so keep at it.