Have you thought about the 1/3rd Toni Clarke kit one, I'm sure you would be able to re-engineer it to suit. Just a thought, think the kit costs about 70 euros.
i have a flair tiggie if you want i could photograph and measure it up and do u a cad drawing will take a couple of weeks to draw it up or i could just draw it out on paper
alternatively try looking go the Stamp undercarrage drawings they are similar in design, i think?
