ok the boost gauge should be hooked up somewhere after the throttle body. assuming it measures vacuum also, but its the best spot as this is the boost the engine is 'seeing'
if its hooked up somwhere near the boost solenoid, thats the wrong spot.
for the manual boost 'controller' depending on what type it is, series or parrallel, youll need to get an installation diagram to make sure you have it all in
but to make sure thats not the problem, put the factory one back in and make sure there is no surging.