IIRC, run a vac line to the bc, follow the arrows, then from the bc to the bottom nipple on the wg. The upper nipple needs to be vented to the atmosphere
Most boost controllers should be adding pressure to the top port to emulate more spring pressure. Its the most consistant way to add boost.

Meth is a great idea... You won't need 60s unless you're aiming for over 400whp and you can leave everything else stock.
Meth is a horrid idea. A good intercooler is cheaper, easier, and 10000x more reliable. 60# injectors will take 93 octane to well over 500whp. 42# will work fine up to about 450whp

Considered Northstar TB but heard they are sort of tricky with their response and road manors. If I jump to large injectors and TB, is my fuel economy really going to suffer or will those improvements only really benefit the WOT overall output and not effect the MPG's?
Nothing is going to decrease fuel economy other than possibly a giant cam... even then its mostly because people are dumb. I run a stock throttle body to well over 700hp.... it works fine.

Running stock in-tank fuel pump with no issues now,
That you know of. I imagine the only thing holding you back from even 300whp is a fuel pump. Go OVERKILL on a fuel setup and you can easily go up to 16/17psi of boost without making a single other change.... I put down 440whp with excatly your setup on a ST2 cam years ago. I was able to turn it up after a giant IC was added to about 19psi and put down 505whp.