Yes, you can tap into your bov line with a t-piece for the boost switch, it isn't important to have the tank above the pump with this kit, once the line is primed and providing you don't run out of fluid you wont have any issues with air in the line, the nozzle has a check valve incorporated into it, when your pump is inactive the system is closed, thereby retaining line pressure.
Check out the US forums for some mounting location ideas, there are some great discreet boot mount set ups that have been done with the 6's over there, just need to get a longer hose to the engine bay.
Nearly all men can stand adversity. But if you want to test a man's character - give him power.
Abraham Lincoln