"I may also have to think about creating a back panel. My main reservations are after how to I screw back the back panel when the whole body is hollow. Is there a way to create a bevelled edges where the cavity plate can sit and can be screwed down?"

I see on VH2580's build (https://www.buildyourownguitar.com.a...l=1#post132895) that he glued some supports on the inside of the created hole to take the screws. I do not think the back is deep enough to bevel or route a recess! Alternatively - does the cavity cover need to sit flush with the back? Could it just sit on top of the wood? The tremolo cover on the back of Strats is not recessed.

Also, the stains look good. I really like the yellow and red! Just be aware that stains will/can look different on different types of wood, and that the final coats can also affect the colour of the stain.