Turn the wick up little by little. There are an infinite number of settings between sending a rod through the block and getting a nice shove in the back. You know what you're aimng for.
As an aside, people forget that charge temperature plays a huge role in power production. Cooler air for the same boost pressure will generally make more power. More oxygen , more fuel can be burnt, and more energy can be obtained.
The problem that you had was not boost pressure but peak cylinder pressure. You have to retard timing just a bit when running such a high boost. Unfortunately, without a direct measurement of cylinder pressure, it's a guessing game at best. Keep in mind that new diesels do run these types of pressures and even higher, without failing.
As an example, here's a plot of cylinder pressure in bars for a 2 litre 4 cylinder common rail engine making 200 N-m torque (BDC to BDC during compression, injection and combustion):