Well, here's the summary:
1) frustums of cylinders are easy, cheap and very effective for the purpose
2) four works but eight is twice as good; no need to skimp at the $2 price tag - use eight per basket
3) aquaseal is the best adhesive I found, although 'plastic surgery' appears to be another worth testing out
4) Flattening the tips of the cones is a consideration for those who tend to hit their knuckles on cones. I don't have that problem because of the way I strip retrieve, but I could see how that would occur and it's worth thinking about.