PnP Vent Check Valve Location

[MaliWop]

I tried searching but couldn't find an answer.... I have 750lbs PnP's in the rear lockers in our 2012 22 MXZ . I am going to tee vent lines into the hard tank vent lines so that we don't have to monitor as closely when filling. I'll be installing check valves. My question is do I install the check valve between the bag and the tee? Or do I install it between tee and the TH port. My initial thought is to install it between the tee and the TH port. 

Thanks in advance. 

[04 VLX WINDERMERE UK]

My thought is, if you are connecting  the vent to a separate connection on your 750 sac, why have a check valve at all? It would also make winterising more difficult as well.

I am thinking of upgrading to the Eight.3 PNP bags but dilemering on a auto vent arrangement as they only have one connection on the top of the bag?

[MaliWop]

From what I have read, the check valve helps with drainage on the 1st Gen PnP systems and it will also get the sac's nice and flat when drained. It should also eliminate any worries of losing water out the Through Haul Vents when the Sacs are full and I'm running listed. Seems like an easier and more beneficial install than running the vent lines to the opposite side of the boat.