Hi Andy,
Aren’t antennas fun! yes we can talk about elevated radials and whether the feed should be part way up the mast but this design is for the board to sit at the bottom of the mast and hence the radials get laid out across the ground. That’s not to say it couldn’t be mounted further up the mast with it’s “Hi-Tech” mounting system (2 rubber bands).
The PDF does say “Use four 10’ counterpoise/ground wires attached to the ground wingnut” - so 10 foot radial wires. But I think you found that. How can this document be so “invisible” in places - that’s at least three of us that have missed things that are in the document, in black on white! Crazy.
My idea would be to cut radials to different lengths for each band the antenna works on, (three in this case) then tape them together for convenience and lay out the “bundle” in the opposite direction from where I hope to get contacts from.
73 Ed.