In class where you want an A you answer get springs set up to near 050 from coil bind
In the REAL world nothing could be farther from the way it usually happens
Think about Dart for example--they sell thousands of heads with springs that will work well with a wide range of lifts up to a certain lift--so does Edelbrock etc
So you are never at that magic number
Take a set of heads to a REAL RACE shop and spend big $$--or have them build you a serious race only unit and..guess what? you get the springs ( usually high quality PAC or others) set up exactly on the edge of about 050 to 060 from coil bind
Do that at home and get trouble--you FORGET to check the all important inner didn't you? and IT is the one that binds and friggs everything up--and you were aimin to impress by getting it " like the big boys do" right? Whew!! Big mistake for home builders!!!!!
I have built hundreds an hundreds of race engines that had all kinds of room to coil bind--with a GOOD driver they win races and don't fail!!
Valve springs usually fail for several plain boring reasons

#1 Tool steel they don't lose pressure--but...those darn things break!
A failed spring is a tool steel spring--ever wonder why there are millions of sets of high dollar springs on Ebay cheap--they run them ONE race and toss them so they don't break
#2 Interference--something is banging into something else--simple--you did not build it right and do not know what the heck you are doing
#3 They floated because you rev'd them beyond the limits of the cam/lobe design/part used/ etc You again--screwed up and maybe don't know how to drive a RACE car
#4 they did not have enough pressure to control your "dumb azz custom cam" that you should have had an engine builder spec out instead of the 4 week guy at COMP ( try Bullit or Jim at Racer Brown or Cam Motion and keep on winning)
#5 valve train is HEAVY ( because it is a Mopar) and again you do not have enough spring to control that fat girlfriend of a cam lobe spec'd by a damn computer that has never raced anybody
#6 you failed to use Titanium retainers--if you did not use them you do not know what you are doing--repeat this several times before you go to bed tonight
Silicon springs do lose a little pressure but they never break unless you bang then into something else Me likey!!!