Loosening the shoulder straps would help you get into the rig. This would also allow the tanks to drop further down your back. Valve drills need to be performed in future dives, but now no. You can then tighten the crotch strap up so the waist harness forms a slight V. This will keep the rig down on your body and tighten the shoulder straps.
Most people should not be diving steel doubles without a drysuit as redundancy. They do make dual bladder wings though. Empty your BC and "try" to swim your tanks up when full. Probably pretty hard to do if not impossible to do when weighted properly.
FWIW I am starting my gal in a drysuit, full HOG system, long hose, etc, but in a single tank configuration. At 107 lbs she will be diving steel HP80's for a long time before/if ever she decides to dive doubles. We will introduce a can light very quickly once she is OWC. I have a couple HP100's if she ever needs bigger tanks.