Perhaps you are approaching the pricing backwards. Why assume that the attributes are slotless?
Start by pricing an innate (as a continuous Su ability) armor bonus that DOES use the bracers slot. In Magic of Incarnum terms, that binds the Arms chakra.
Should that only cost 115% normal? Personally, I don't think so. That sounds like 130% or 140% to me.
Combined with slotless, that would be 230% or 240%. If that seems like too much, maybe don't make the effects spotless.
--
gnfnrf
Start by pricing an innate (as a continuous Su ability) armor bonus that DOES use the bracers slot. In Magic of Incarnum terms, that binds the Arms chakra.
Should that only cost 115% normal? Personally, I don't think so. That sounds like 130% or 140% to me.
Combined with slotless, that would be 230% or 240%. If that seems like too much, maybe don't make the effects spotless.
--
gnfnrf