Borimer:
1) using only 1 or 2 men/bombardment engine is good, with the rest of the forces divided up to defend the main gorge and the 3 northern inlets. we can have a smaller force at the inlets, with the ability to call for reinforcements if overwhelmed or the bombardment engines are in trouble. the main part of the forces will be able to defend the gorge, but we should also set up some ambushes (at least one) at the gorge as well
Agreed for the most part. However, if we only use 1-2 men per bombardment engine, we're limiting ourselves to light/medium ballistae and light catapults only. Good rate of fire and good to moderate accuracy, but not much damage or AOE there. I think at the very least, we should allow for some light cannons, which are accurate and decent on damage and AOE. Light cannons require a crew of 3 men to man them, which isn't too bad.
Borimer:
2) the sunray should be focused on the gorge, but it can easily (?) be turned to focus on the inlets. for the inlets/gorge division of engines i propose a 70/30 split (or thereabouts), with the 70% defending the gorge
That might be doable. Hopefully the scouts and earthroc riders can warn us in advance if we need to position more defenses at the northern inlets for incoming enemy units.
Borimer:
3) 1-2 men per engine should be enough, unless we want one or two to be a faster/better unit with 3-4 men
I don't think you can improve an engine's rate of fire or other stats beyond those listed in the table with extra crew. I think those numbers are each engine's optimum performance. Also, see above for why having only 1-2 men per engine might not be a good idea.
Borimer:
two light cannons, and the rest light catapults
I'll note that down as one possible strategy to compare with others.
Borimer:
perhaps the engine with 3-4 men could be here, fast RoF and the ability to turn quickly
Actually, the engines with larger crews tend to be the ones with slower turn rates. All ballistae and light-medium cannons and catapults have a 0 turn rate. It's only bombards, great bombards, heavy catapults, trebuchets, and heavy cannons that have slow turning rates. I definitely agree that we shouldn't put any of those up there. We should put something there with a 0 turn rate (meaning it can turn 45 degrees in the same round it fires, or 90 degrees if it doesn't fire that round). If we expect less frequent intrusions from the northern inlets, then a light cannon might be the best choice - accurate, fires once every 15 rounds, and requires a crew of 3. If we expect frequent intrusions, then a light ballista would probably be better - just as accurate, but fires once every 8 rounds and requires a crew of just 1.
Borimer:
we need to know which direction they are initially going to attack from, ie the gorge, the inlets, or both. the sooner the scouts can get this info to us the better off we will be
Agreed. I plan to have Adaran, Duanthar (Polyanthar's ranger), and 5 rogues scout out the northeast inlet, and suggest that Naj and Arthure each take 5 rogues and scout out the other two inlets. Then each group can post a few sentries to keep watch of the inlets (spaced apart at shouting distance so the front-most sentries can holler down a warning that gets passed along each chain to our forces whenever approaching orc units are sighted). Another option would be for earthroc riders to remain stationed in each inlet, keeping watch until approaching enemies are sighted, and then fly back to warn us immediately with details on what's coming. I think both could be viable tactics. One is stealthier for when we don't want the orcs to know we've seen them, one is faster for scrambling defenses in emergencies.