Valve float was largely a phenomenon of the 1970s when computer generated fast acting lobes started to appear, and Spintrons and high speed photography hadn't caught on yet (or been able to be affordable for the small guys). Spring surge, "fuss" points, and harmonics were not much understood yet, by the small cam grinders anyway. Their "solution" to a misunderstood problem was to make the lifters bleed off quicker. Back then when lobe design had eclipsed spring design, float was common. In the last 20+ years we only see evidence of float mebbie once a year, if that, and almost never from the major cam companies products, and usually the end result of a "mix and match" approach to parts purchase, and desire to save a few bucks.
Using the springs and retainers from the same company, of the same set of parts, designed for each other, and employing the correct installed height, in the proper designed for operating range, pretty well guarantees satisfactory results. Small companies that don't have all of the required bazillion dollar research departments are the ones that have surge, harmonic, and float issues.
The small companies that only grind cams, and buy others ancillary parts from wherever is cheapest, are companies we stay away from. Do you really think that some small company that grinds a small amount of cams, and has claimed to have "re-invented the wheel" has anywhere the amount of resources to investigate all properties of their own, or everyone else's parts?
Why do you think that the large companies are not following the lead of these small guys? Even I have a cam analyzer, an inexpensive one is less than $5 grand, so I can analyze cam profiles. With one of those anyone can analyze every degree (of the 720 degrees in the event) to a 10 thousandth of an inch and tenth of a degree. So there is a reason that the big guys are not copying what the small guys are doing, maybe the profile makes power, but at the expense of valve train stability or longevity. Its the same deal with the header companies that claim to make more power than everybody else, all it takes to find out what is happening there, is a ruler, dial veneer caliper and a dyno.
As far as hydraulic roller cams are concerned, I was the unwitting "guinea Pig" of a then large companies new hydraulic roller cam program in the early 1980s. I figured out their problem in a couple of weeks on my own, and when confronted, they admitted their errors. Search this and other boards for "hydraulic roller lifter issues".
Trust me. The big guys all know what the small guys are doing, but the reverse can't be said. JMHO TIMINATOR