Re shields: stats and graphics are totally unrelated in a mechanical sense. The reason some shields have reduced effectiveness is that the units are already so well armoured that adding a shield doesn't make a great difference to the level of protection.

Hmmm, distances I'm not too clear on, but that sounds reasonable - I could never throw a javelin much further than 25m (though I did set the record at our school for a while ) There is a formula somewhere relating the distance unit used in the prod files and "real" distances, but it's not something that I've ever really thought worth sweating over....

I don't know the exact moment a "charge" ends. It probably varies in different situations, depending on the unit charging and the unit being charged at, and also terrain (I expect an uphill charge to falter more rapidly than a downhill one...) I would expect a charge to be over once the unit has come to a halt, or significantly slowed down, but again, it's one I handle more by "feel" than any hard and fast stats. You can tell when your horses start dropping like flies