yeah, so on doubles I much prefer the DST routing. I think having the secondary come from the bottom port and straight over from the left, then the inflator doing the same from the right post is the best routing for doubles, and when sharing air it allows the long hose to donate to the full length so there is no risk of it getting pinched off *however low that risk is, is irrelevant, it is better that it is going straight out*.
In sidemount I could take it or leave it for the turret and fifth port, but I am learning to accept the advantages of SPG's coming up, primarily when using a DPV so you can check the right bottle without stopping and have a much easier time checking the left bottle. I don't like it because everything is going different directions, but it is a compromise. I dove Poseidon 3960's for a long time in sidemount and thing the whole thing looks a lot cleaner, but sacrifices had to me made. I don't think the bottom port is necessary in sidemount, only advantage is in the drysuit inflator but as soon as you have to push a bottle forward everything gets weird. I much prefer all of my hoses to go down then back up to where they need to go then have the turret swivel and have them in my armpit.