Found an interesting piece of info regarding FE3 lifters.
It appears as if KIA variant center hla units are .8mm taller then true mazda pieces retrospectively
wanted to pick peoples brains & see what/how they might effect lift/if it would yeild the valves being partially open on no load(obviously we don't want that)
Mazda lifter buckets are taller then Kia varients & have a tapered oil induction into the bucket. ~2.5-3mm taller on the lower skirt
the center HLA is 3 pieces. the bottom portion which contacts the valve is another smaller bucket that gets filled with pressurized oil.
Kia's have an additional .7mm height difference in this piece alone. (same inside diameter & depth for oil capacity)
the piece which pressurizes the lower bucket has an additional oiling groove in the kia units. not entirely sure the purpose for this... perhaps additional lubrication to prevent sticking