Thanks gents, much appreciated!
After the last few builds with scratchbuilt tail feathers, I'd decided that the plain plastic sheet was too bland, and the micro masking tape strips were too big, so for these 2 I'm trying something else. I attached thin strips of .005" card, and then gently sanded them down even further.
Here's what I started with, just the strips added:

and a comparison shot:

So far I'm pleased with how they look, a coat of primer will reveal the truth.....
A little more progress on the floats too. They've been joined together, and I've made new struts from .020" x .060" strip, thinned down slightly as .060" was a little too thick, but .040" was too thin....

Thanks for looking in!
Ian