ok, so this needs to be noted. Yes I am a fan of DSS and yes the above poster is correct, you will be directed that way for a myriad of reasons all of which are 100% valid. I own multiple DSS rigs, and also own multiple transpacs *one is a Transpac II from quite a while ago, the other is outfitted to my Nomad XT*.
The Transpac is a brilliant rig for what it was designed for, and it does it absolutely better than any other rig on the market or really ever made that I'm aware of. The problem is the number of people currently doing those dives are probably in the single digits *backmount doubles, hiking through the jungle*. It truly does it more comfortably than a hard backplate and wing and that is exactly why Lamar developed that rig.
Now, up until I switched to DSS rigs I was very outspoken that not everyone was able to comfortable dive a single piece harness because I wasn't able to. The DSS rigs are long enough that it puts the straps where they are supposed to be, and as such I can quite comfortably walk around in doubles again. If for whatever reason you think that you need/want the padding, which you shouldn't unless you are always diving without any neoprene on, and have to carry your tanks for quite a long way *not common circumstances*, then you can always put something like the Transplate harness on any hard backplate which gives you the comfort harness, and you can also zip tie some neoprene to the backplate, or buy any of a myriad of aftermarket backplate pads. Can get them from a bunch of places online. Again though, you don't need any of it unless you are walking long distances *more than 100yds*, without any neoprene on, or you have some shoulder problems where you should probably yield and go sidemount if your shoulders are messed up