I really can't tell the differences between T20, ATX40, TX40 and TX50 mounted on various Apeks 1st stages. The barrel is exactly the same. As for the internal on various Apeks 1st stages, only the FSR is slightly different because the valve seat is replaceable otherwise same all round.
DST fit the requirement perfectly for the OP. But the cost and availability of service kit to the general public is the most concerned.
DST fit the requirement perfectly for the OP. But the cost and availability of service kit to the general public is the most concerned.