I have been using Easypoxy for years and I like it.
For filler I have always used WEST system epoxy and phenolic microballoons, which can be gotten in bulk or mixed with fiber in the form of WEST Low Density Filler. I used to buy the balloons industrially because I used so many.
The Gougeons provide more application information with their products than anybody.
I like the epoxy/microballoons mix because it can be made to the thickness you need, can be carved with a dragon's tongue when still soft, and sands nicely when fully hard. I have always used a sanding block to level it, and have a number of them with different radii for inside fill.
I like to roll High Build Epoxy Primer over the prepped metal, and where that doesn't fill, I use the filler.
The trick with easypoxy is to get the first coat on really thin, thin enough to see through if you can. I use a fine roller, and have never found the need to tip. I suspect that if you have enough to tip, you are putting on too much easypoxy. Just keep rolling until all the bubbles are gone. Three thin coats are really needed, use one of those foam blocks to break the surface between coats, unless the timing is perfect. A little thinner will make it easier to get a good shine on the top coat.
Be sure to read all the stuff from Pettit.
I get results with Easypoxy that are far beyond my skill.
1975 32' Flybridge Sedan, twin Perkins 6-354 diesels, 1:1.53 velvetdrives, 16 X 19 props. Merritt Island, Florida