Hi Jim...

I am not aware of any old vs. new long vs. short trap wires... there are old and new style shrouds and the new style shrouds are shorter than the old stuff - but trap wires???
Part of your length issue is maybe your keyhole setup. Looks like the part that replaces the dog bone (or H handle) might be a bit longer than the dog bone.
Some of the older harnesses (bucket seats) allow for quiet some pull away from your body - creating additional "lenth". The newer harnesses will stay closer to your body and make stuff more controlable.
Rope lock... on the pic's it looks like the rope lock would "lock" at a point when the ball of your hey hole setup reaches the level of the side bar - it might even go a bit past the side bar if you pull with 180lb.
Practice... 50% of the time I sail single handed - My first attempts on the wire, handeling main sheet and a two meter long tiller extension did not turn out well. I moved the rope lock so that I would stand higher on the rail and so I would not take a dive when I would move my butt over the edge. Over the last months I gradually lowered the rope lock. A good starting point for me was to place the eye of the dog bone about an inch above the siderail.
Getting out on the wire... I typically start from a position hiked out wit a foot under the straps. In this position my butt is already past the side rail. I hook to the wire and lower untill the wire carries my weight. the rest is about the same as befor... forward foot pushes out other foot follows - that all without any manipulation to rudders or main sheet. I tend not to cam the main in.

Patrick