Hi Greg
As you suspect, the ratio is the problem there......whilst most would think a 6:1 overhead is good for jigging, it is just awful. Whilst beautiful reels, I don't like Torsas for that reason, and whilst I love my 665 - if I owned his high speed brother - well....that reel would as does yours relegated to more shallow work. My reels are mostly either 4:1 (Accurate 665) or 4.9:1 (Progear Oceanus). The Oceanus gears are cut on an angle which gives increased cranking efficiency and allows the slightly higher ratio.
In addition, standard crank arms on most overhead reels are pathetic and no good for jigging, way too short. I replaced the 665 arm with a jigging master power arm (11.5cm) which gives you much better power and speed. Look at Shimano OJ 'vs' trinidad - same thing. While we are on the topic, one way bearing anti-reverses are of limited strength, the JM double docking set fixes this. Add a JM T-Bar and you have a perfect reel for jigging - or just buy an Oceanus with all these features built in! Fellas, this isn't meant to sound like an advert, just that JM design after market upgrades to make already good products better.
Anything deeper than 100m I would call deep water. Most of our metro jigging is done in 90-125m (mainly 110m) and I intend to try a couple of spots in 190m this winter (for giant AJ's!!!)
Andrew