M70 MOA Trigger options?

What choices are there for replacing the MOA Trigger? How difficult (or is it even possible), to retro-fit a pre-64 trigger assembly?
I'm dissatisfied with the performance I've been able to obtain with the MOA trigger system and ideally would like to find a two-stage target trigger.
So far, I've only been able to determine a Timney #402 (single-stage), as an option.
I'm waiting on my Bartlein Barrel and am looking to changing out the MOA when I install the barrel, true the action.
Thank you in advance for your knowledgeable responses.
I'm dissatisfied with the performance I've been able to obtain with the MOA trigger system and ideally would like to find a two-stage target trigger.
So far, I've only been able to determine a Timney #402 (single-stage), as an option.
I'm waiting on my Bartlein Barrel and am looking to changing out the MOA when I install the barrel, true the action.
Thank you in advance for your knowledgeable responses.