OR-2050 is an -014, but I have to verify the other two.
I assume you are talking about the second stage seat? It is flippable. But it's available as a separate part and should only cost around 3 dollars/euros/yen(x100). For example:
Mares regulator second stage valve pad 46184062
Rubber pad for Mares regulator second stage valve fits the following models: FUSION, PROTON, MV, ROVER, PROTON METAL, ABYSS, CARBON, PRESTIGE, AIR-CONTROL, PRESTIGE DPD, INSTINCT, NAVY Diam...www.maremossoforzasette.it
I don't have a schematic either, but externally it looks to be the same setup as the 22 family. They don't require any special tools other than something long and thin to push the HP seat (aka volcano orifice) out from the diaphragm side of the body and snap ring pliers if you are using a yoke instead of a DIN valve.
Mares does have several white plastic tools for pushing some parts out and keeping others aligned during reassembly, but you can use wooden dowels of various diameters instead.
I suspect you'll be happy, the assist from the VAD (bypass tube) makes for an easy inhale. (Anticipating Nemrod's response) I have never found the exhaust effort to be noticeable.
I do not know what size exhaust valve is in the current Mares lineup. I am sure it is a full size 30mm+ in order to meet CE WOB requirements (?).