I recently grabbed a second hand Flamespyre Phoenix with the plan to put an Eldar Farseer/Warlock on its back and use it in my little Eldar force.
I quickly realised he was too big for a 'counts as jetbike' but was dimensionally very similar to a Crimson Hunter, just with his wings at the front rather then the rear. While I like the idea of using him as a fully fledged Eldar flyer, the psyker on his back means that it makes more sense to run it as a Hemlock Wraithfighter.
I wanted to use bold colours on the model but decided not to use the heavy highlighting on the feather edges that I'm seeing on a lot of Tzeetnch models at the moment. The look works really well on daemons, but didn't fit with the image I had in my head when planning my approach for this model.
I painted the Phoenix itself by blocking in 3 bands of colour (dark blue, light blue and pale grey) and then mixing several intermediate shades and feathering thin layers of them to blend the zones of colour together. Lifting the grey areas towards white without getting too bright was difficult but seems to have worked out alright.