I am about to start the finishing process of my Barracuda and I have two concerns:

1) I have some of Randy Smith's Areo filler, which I've never used before. I'd appreciate any advice as to where and how to use & mix it properly. I don't want to wind up with a lumpy mess that may be difficult to sand because of my inexperience with the product. It's best to ask first. Can the filler be mixed with either nitrate or butyrate dope?

2) I decided to "sheet" the outside of the canopy with clear plastic rather than try to inset the windows into the canopy frame.  So far I'm happy with the result. I will just mask off the windows before color painting. Can I spray clear dope directly over the unmasked windows as part of the final finish steps, or will this ruin the windows? I've never sprayed clear over a canopy before. Here's a picture of the canopy area. The cockpit is rather small and I had to set the pilot low down, otherwise his helmet hits the windows.

Dennis,

As far as Aero-1 goes (Randy's zinc sterate filler), mix it up as you would if you were using talc. Takes a bit less than talc and sands very easily.

On shooting clear dope over the canopy, the answer is, it depends. What is the clear plastic made of? With PET or PET-G (as is used in most modern canopies) it's not a problem. You can shoot topcoat right over the plastic. If you used acetate, then it depends on how much thinner is in the dope. Thinner can eat acetate if you're not careful. If you shoot catalyzed polyurethane, that can go over most acetates as long as you don't get too heavy handed with the spray gun.

Dennis,

Yea, My usual refrain is, run a test. Take some of the material, put in on a wood frame and shoot some tests. Could be that shooting on the clear will work fine.

Did the "Cuda" ever get finished. Growing up, this was one of my favorite planes and this build looks exceptional, just wondering??

Unfortunately, not yet. Life got in the way with other priorities. 
It's hanging on the wall along with six other models that need covering & finishing. One of these days ..............