Today I finally found some green fluorescent clear 1/8" plastic in a craftshop for a few pennies [below] and located it in a PST CaK eyepiece. The green converted view was the brightest yet [due to its thickness] but as I suspected diffusion through fluorescence fuzzed the image so the limb was difficult if not impossible to focus.
The plastic could possibly be thinned for a clearer but inevitably dimmer view. It's over to those working in labs with superior materials to solve this one
My best effort remains a six stack of fluorescent stained Sellotape but result, if bright, marred by imperfect contact with each other on glass base.