According to my RTA (French equivalent of your English Haynes manuals), mechanical fuel pump pressure is 0.24 to 0.38 bars which is about 3.48 to 5.51 psi. When it come to fuel pump, better having too much pressure and a fuel pressure regulator, than not enough. The Pinto mechanical pump should do the job for your bike carbs, but I would add a fuel pressure regulator (low pressure) if there is none in your installation.
Only my small opinion according to what I know about that
Hope this will help.