Finished reading it and a few quick observations seem to be warranted. In no particular order.
The Jane's naval wargame rules, like the contemporaneous H.G. Wells Little Wars, relied in large measure on actual physical "shooting" by the players rather than the dice-based systems common to modern wargames. In H.G. Wells case the palyers actaully fired bullets from model cannons at the enemy forces. In the Jane naval wargame the players poked holes in a paper diagram of the target ship using a wooden tool with a tack point on the end. A very odd fixation, really.
The Royal Navy wargame rules are definitely based on providing a training experience and not being a competitive game experience. As a matter of fact, competition is explicitly discouraged! One notable thing about these rules is the way that gunner hits are figured. It's a very deterministic system with the number of hits being based on how many guns are fired and for how long with no random element at all. Likewise damage is an average value. There's no provision for fluke events, lucky shots or bad fortune in general.
One notable thing in Jane's rules are the very short ranges envisioned. The rules devoted considerable attention to battles fought at ranges under 8,000 yards (with 2,000,-4,000 being treated as average) and his tack-poker combat system seems to assume that ships will engage in low trajectory direct fire at relatively close ranges. As it turned out, of course, the combatant navies were in the midst of a gun and fire control revolution that was going to mean that most battleship actions would take place at ranges two, three or four times farther than Jane assumed.
The small handbook written by Jane (based on internal evidence, just before the end of 1914) is a fascinating document. Obviously meant for the general reading public, the book has a bit of a jingoistic flair and also makes certain social assumptions that seem rather odd to modern ears. In particular the strong class-based personnel system used by the British is accepted without question.
Jane had some pretty insightful observations in the handbook, however, and definitely seemed extremely well-informed about likely technical naval developments, but he wasn't much of a seer on how tactical and strategic events might play out. He showed little understanding about commerce-raiding nor was there any hint of what a submarine blockade might entail. He notes that the war was expected to be over before any 15-inch gun battleships might be ready for action -- a common enough sentiment in 1914 -- and seems to have expected that a clash between the two battle fleets was imminent. As it turned out the battle fleets would not meet in action for nearly two more years and Jane, himself, would not lie to see that day.
All-in-all a very interesting read.