Well, within the rules, I would try and stick with a medievil viewpoint of science and motion - which i would imagine would be along the lines of "The sword is as light as a feather, but its still sharp and hard and so therefore hurts people when I stab with it" and so apply the same (simple) thinking to the armour - its hard and tough, but has no weight, therefore the horse doesnt feel the armour's weight, only the persons weight - all the armour does is give the poor victim of a colision something solid to hit instead of a soft person and make sit slightly more difficult to get up afterwards as it restricts your movement from its inflexability....
But that doesnt matter as long as the SG has decided how to handle it(AND sticks to it consistently).
As usual, we prefer to run things realistically as far as possible, because in reality there was no "medieval paradigm", but hundreds or thousands of them(and commonly very badly conflicting with each other).
Which one of them? There wasnt ONE such viewpoint.
Another example, can you chop wood with a weightless axe?
In reality, yes. But going by your above choice, not a chance, because it NEEDs the mass behind it to split the wood.
@Direwolf - yeah, i agree with you there - but i like to keep things simple, so I wouldnt bother thinking about it in the end (and im alpha SG) - im not a particularly strict SG.....
@Thumper - the items effect is from a spell in HoH:societies, which reduces metal armour loads to 1 or 2 (partial or full), and it doesnt have any requisites, so thats what I based the enchantment off...
I see it. Pg 38. Still don't like it. I'll have to house rule it in my campaign. I guess it depends on if there is enough metal in the metal reinforcing to make the same appreciable effect as in chain. Good call going to an established source for the design.
I would say it is a Casting Requisite and thus does not affect the Lab Total.
It also depends on the armour I suppose. If the metal of a suit of chainmail is made weightless, I don't think the straps or buckles make a significant contribution to load and burden.
The spell he's using as a guideline makes no distinction on the effect to load for either of metal reinforced leather, metal scale, and chain. The spell effects them equally. This may have been just to keep it simple. I'll probably house rule it.