you're not "jerry rigging" anything by making valve spring pressures as close to the same as you can from valve to valve. and you think widely different valve spring tensions don't make a 4 cycle engine vibrate, go talk to some NASCAR engine builders. I built racing engines for anything from a 7 time Midwest Region SCCA champion E-Production racer to Alcohol fuel rail to Briggs WKA gokart engines. and in every case,.....valve spring pressures watched closely for valve float (the obvious reason you state) and uniformity of compression because the engines vibrate less when the springs are within a few lbs of each other... widely differing pressures are what set up destructive harmonics in a valve train. and "float" is not what destroys valves, float is sometimes used to prolong open valve timing and is sometimes deliberately built into a valve train where the rules limit valve timing and lift. it is the valve slamming shut and bouncing, that causes more problems, and that comes from something other than spring pressures.
I could go on,...but it seems like you know it all already.
as for answering a 6 year old question,.....I guess the problems people had with valvesprings 6 years ago, don't happen now anymore,...right ?.