Help with toplac

I have had a lot to do with tinting paint over the years and I presume that that paint tints have remained the same formulation. They can be used to tint anything from cellulose to water based paint but you must mix properly. What is not usualy stable is blue. It goes green !! The main problem that you have is that when starting with white you will only be able to produce pastel coulours. You can never overcome white pigment. If you do want a pale blue Lark like all the Parker 2's ?
use artists oil colour as a pigment it should mix as I believe Toplac is an oil based enamel. So we look forward to a pale pink Lark, I painted one Datsun purple once, very fetching. Remember however that adding pigment will slow down drying time, the more pigment the longer it takes. I have used Hammerite garage door paint on plastic boats applied with a short pile gloss roller. That works well is durable and fairly cheap particularly at B&Q on a wednesday with your old duffers card.

Not sure on the colour tinting...

Mixing sugar or sand in with the paint has been mentioned a few times as a good non-slip surface. The sugar is suposed to be particularly agressive as it disolves out of the top surface leaving a very rough finish.