Hi John,
Excellent work on the signals, a big improvement on the out of the box jobs, you mentioned using 'Solartrim' I don't know if you know but there is a product on the market called 'Trimline' by 'Model Technics' it comes in a variety of colours and I think there is about ten different widths of pin stripe on each roll.
If anyone is thinking carrying out the same mods as you it might be worth having a look at 'Trimline', it might save the need for the double bladed knife.
Michael