It was my thoughts to run a lower boost level (maybe 0.5 BAR) but I know it may be a little tricky to get the fueling right at those levels - when I start to put it all together, maybe I should look at some Glanza injectors instead and just increase the fuel pressure (with a decent pump of course)?
you will need to run a decent fuel pump to begin with the paseo pump will cause major issues with a turbo, see if you can get your hands on a second hand GT4(ST205)/MR2 turbo/Supra turbo (Mkiv) Fuel pump. the pump assy should be a relatively straight swap. only go for the chassis types stated though as the earlier models (ST185, mkiii supra) use a significantly larger pump and operate in a different fashion.
You would be able to get away (safely) with running the 370 injectors on the Glanza Ecu with any of those pumps, I can understand your caution with regard to boost pressure it is a considered approach, often the best way. May I suggest two option routes?
1) procure a 0.5 Bar (probably adjustable) actuator, rebuild engine using OEM 4EFTE/5EFE mixed gasket sets
2) use the turbo's standard actuator (usually 0.7 Bar) but when you rebuild the engine for the turbo setup use a decompression plate / thicker headgasket (this would not have to be an aggressive one, I'd imagine the TRD thicker gasket or Athene MLS jobbie, about 1.2mm would be sufficient, not more than that otherwise you wouldn't feel the benefit.)
Don't forget that the turbo from the kit is not is CT9 and as such behaves differently. I didn't manage to find a compressor map in the time which I had it but they may be beneficial to you if you can get hold of one. If it is tailored for low boost, spooling nicely at low rpms then your planned build should be good. if however the map shows its designed to deliver more boost at higher RPMS then lowering the compression maybe a bigger factor.
Alternatively you could take a traditional starlet approach which would be to build it all and drive it til things go bang?