If your penny washer, and wear is this bad, I wouldn't leave it too long before a recon one, they normally wear in the actual housing, the crack in the seat as there always is doesn't normally cause a problem, but new turbine housings are £150, if not already done so a 360 bearing needs to be in there with any rebuild at stage 1.
As said 1 bar is the norm for stage 1, or 14.5038 psi!!
tabetha