Seems a lot of money to coat such a small area! I think that there are a number of alternatives to this.
Firstly I used the best I could find on Calista’s transom after the accident. I used a special epiphanes 2 component varnish which can be overcoated after (I seem to remember) 6 hours, to build up 6 coats quickly, and then used 2 coats of ordinary epiphanes varnish to add UV protection to the finish. The special 2 pack was £75 per litre – and I have loads left over. The ordinary stuff was in the order of £25 a litre. I am sure I must have described it in the blog at the time.
I have also experimented with the cheap “yacht varnish” which you buy from DIY shops. Here in Wales the cheap supplier is Wilkinsons – I suspect they are a nationwide chain. It is about £12 per 3/4 litre. I would use a coat of boiled lineseen oil brushed on liberally onto bare wood. Apply 4 coats of varnish on top starting after 24 hours. I recon that gives a self healing effect in case the varnish gets scratched. I have used that succesfully for many years.
Whatever system you use I think that it is important to give the varnishwork a quick rub down each year and add a fresh top coat to renew the UV protection. Keeping the varnishwork out of the weather in the winter, and adding a fresh coat each year really does make it easy to keep varnishwork looking good with the minimum of effort.
I have not had to strip anything (mast, boom, toerails, coachroof, cockpit) back to bare wood in the last 10 years.