Sounds funny, "rule of thumb", specified down to the nearest micron.
Anyway, that's .015", and I use between .010" and .015" for a 4 string.
A business card is .010" to .012".
If the 5th string is high, as in 'C' above 'G', not high action, a 4 string relief value should work just fine.
If the 5th string is low, as in 'B' below 'E', I would start with a 4 string relief value and only add more relief
if the lowest string absolutely needed it. I wouldn't compomise the other 4 strings unless I had to. For example,
if some extra action height didn't work for the low 5th string, then I would add a little more relief.
Last edited by megafiddle : 11-17-2012 at 08:04 PM.