Probably worth a try just to know if the regulator could control the Turbo pump.
I ran a 1988 S15 2.8 TBI 4x4 a few years ago with the windshield washer reservoir/pump.
At first it wouldn't run with the 35 psi W/W pump without the return line hooked up.
Once I hooked up the return line I ran it for 2 yrs on the W/W system
I forgot about this part until I looked at an old picture.
Believe it or not, I ran it for 2 yrs like that around the yard and the occasional trip to town.
Thanks
Randy