Boost is dependant upon engine load. Cruising is not putting a lot of load on your engine and won't cause it to spool. You can see a slight increase in pressure but if you stay out of wot the positive boost pressure generated is negligible

T3/t4 is too big for what you want to do. Again like the last thread find a straight t3 super 60 , gt25r or t28 that's your best bet

or supercharge