Lots of vague terms there Dougal.
Define these for us in context of this chat.
too much boost
Bigger boost
High compression
A little more ( more than what?)
I boosted my 1HZ with 14psi, was contemplating bumping that to about 18psi. I wouldn't go much beyond that on a 1HZ.
14 psi certainly...
Limiting boost to less than 10psi was probably good advice back when the turbo's commonly being used were mismatched and sourced from petrol engines.
If the turbo is running outside its efficient range and heating the intake air too much, then yeah, limiting boost makes some sense.
There's no...
Agreed the idea that boost should be less than 10psi is outdated.
A well matched turbo and boost compensator, intercooler, exhaust, and correct tune are the important things.