Nasotec VEM spike and shoe footers: any users here?

I need to buy one or two sets of footers for solid state components which will sit on shelves of a Symposium Acoustics Foundation rack that I have on order. I have two sets of Ingress Engineering speaker footers (the ones with two cups and one ball in each set) and am pleased with their effect under a disc player and preamp, currently sitting on glass shelves. I may well order more of those, since they are reasonably priced. Used Solid Tech feet of silence are another possibility. I noticed the Nasotec VEM spike and shoe footers listed here on Audiogon but have not found any reviews of them online. Has anyone here used these as footers under components, and if so on what kind of rack or shelf? What are your impressions of their usefulness in this application?