diversolo:
I recently completed Cavern and am getting ready to schedule Intro as soon as I do some equipment upgrading. My question is: will a Transpac with soft backplate fulfill all of my needs for the forseeable future or should I just go ahead and get a Transplate setup with a backplate? I plan on twinning a pair of E7-100's to start and may go up to a set of E8-119's later on. Which wing should I get so I won't have to upgrade that later? Also does anyone have an opinion on E7-120's? I've heard from some divers that they are not popular due to their height.
Karstdvr made a good post, his advice is excellent, but unfortunaely it did not directly answer your question. My advice is first to listen to Karstdvr, but if your heart is set on buying gear then here goes.
I use a Deep Sea Supply plastic backplate. In fresh water you will almost certainly not need any extra weight and this plate has a center channel of stainless steel to help support the weight of large steel double cylinders. Many companies make Aluminum plates as well and almost any of these would serve you well.
For the harness on the plate I use a simple one piece "Hogarthian" harness. This thing is simplicity in and of itself. You will have plenty of gear to attach to the harness so having one that starts out so clean is a real bonus.
For cylinders, you have asked about the 100's, the 119's, and 120's. I have not used the 100's so I can offer no opinion. I have used Faber 95's doubled and these are really close to the size of the 119's. These are relatively short and if you are a tall male you may find that you get into a head down position too easily. If you are tall and want cylinders in this size range the 120's are a better choice. If you are considering the 120's I have used a pair of Genesis 120's and since I am tall these long cylinders make a better choice for me. If you are short then the 119's would be better. My cylinders of choice at this time for me are the E8-130's these are really close to the same height as a standard Aluminum 80, just a larger circumference.
If you already have a buddy for cave diving, or any sort of technical diving using doubles you would find gas planning easier if both of you use the same size doubles. But don't listen to me, listen to Karstdvr! If you are diving in cave country you can rent doubles in a couple of different sizes from Cave Excursions and other shops for somthing like $10 a day plus gas. Try before you buy, then when you buy you will already know how the tanks will affect your trim.
Mark Vlahos