Armor mod

Armor ACs. Fractions round to the nearest value with 0.5 rounding up, with the exception of a shield. Might be possible to do fractional AC bonuses based on DEX, AGI, or whatever we decide to finally go with.

Shields +0.5 AC
Padded, leather armor, or ring mail vests +0.5 AC
Studded leather or ring mail suits +1 AC
Brigandage, scale, or hide armor +1.5 AC
Chain mail +2 AC
Splint, banded, or non-steel platemail +2.5 AC
Steel plate mail +3 AC
Field plate +4 AC
Full plate +4.5 AC

Anything past +2 AC would suffer a -1 to initiative per full AC to simulate the bulkiness in combat. Pegasus can equip up to splint without a shield before being unable to fly.

Shields would be a special case and confer a +0.5 AC when not in use and slung over the back for shields larger than a buckler.
Bucklers give +1 AC against 1 melee attack per round, and are light enough to be worn without hindrance.
Small shields can protect against 2 frontal attacks of the character's choice per round, giving +1 AC, and the character may use the forelimb that the shield is attached to to carry items, though they may not attack with a weapon carried by that limb.
Medium shields protect against up to 2 frontal or rear attacks per round, giving a +1 AC bonus against those attacks. Due to the size, nothing else may be carried by that limb.
Body or tower shields give +1 AC against melee attacks, +2 AC against missile attacks. Due to the weight, possible maluses might be given as well.