vicp, I know this is old and I'm kind of necroing it....but I thought I'd throw this in here:
AkroEdge and I went diving together. We had the same instructor for Cavern/Intro (and he did my Full Cave as well). Edd did my Apprentice. All of it was in an SMS100. Cavern/Intro was done stock. I did a weekend diving with homebrewed Edd mods. Then I bought a real Edd-mod rig and did Apprentice/Full. The last round is what most fully sold me on going to Edd and diving steel tanks as doing it right. With Worthington LP85's or X7-100's, the Edd-mod rig with tanks clipped to the DR handles on the buttplate is perfect through the range of pressures. I was able to sit at the top of the chimney in JB and let the flow push me all the way to the Grim Reaper sign without moving a muscle. The only reason I had to move then was my instructor decided it would be "fun" to do some lost line drills.
This weekend, I tried diving Al80s. I've done that before and I thought I had had decent success with a 2# weight on the camband towards the bottom of each tank. I don't know why, but one of my tanks felt "off" but I couldn't explain how or why. It just felt off. That was my first day with my new GoPro, and the video evidence showed it. My left tank looked "okay"~ish while my right tank was AWFUL. My left tank was slightly tail up, it looked like it needed another pound on the tail. My right tank was up several more degrees. I felt it during the dive. They were twisting me. One thing is I know they were different tanks. They were different brands and different ages, but I figured it was close enough. I'm going to Mexico to dive with Jason Renoux in about a month and will be asking for some advice on setting up my rig for alu tanks. If I can find time to hop in the pool, I'll be doing that as well...but between the wedding and wedding planning and how annoying I find paying for air just to mess with tank setup, I'm not sure I'll be able to get in the pool before Mexico.
Since my harness is modified into the "H-harness" setup, a sliding D-ring won't work for me. So now I'm looking at placing a couple of d-rings on my waist strap just for ally diving, and I'm looking at switching to different sized leashes. I'll be the first to admit that my current setup is lacking when it comes to ally tanks, but I think I can dial it in (too cheap/stubborn to buy another system). My main cave buddy has an Edd-modded SMS100 and a Razor, he uses the SMS100 for steels in FL and the Razor for ally tanks in MX.
Anyway, if I can make any headway on mounting ally tanks I'll let you know. My current plan is REALLY short leashes clipped to my waist.
---------- Post added August 27th, 2013 at 03:18 PM ----------
pholife: one solution I saw was to use two tri-slides per shoulder and mount a separate "accessory" piece of webbing between them. When you travel, you can pull that webbing out, place a weight on it, and then re-thread the webbing through the other tri-slide. This is for a travel-friendly trim weight. If you put weight on your shoulders, it WILL trim you further head down. If you're diving a stock SMS100, you're probably trimmed heavily feet-down so this might help. Just be aware that adding weight anywhere other than near your belly button/ribcage will change your trim as much as it will your buoyancy.