I think you will have a US ID, so register on the Latam US site. Then ask for a status match.... If they do match you (i have read on statusmatcher that this year are not matching a lot).
You will be able to get upgraded always , since you will end up as a Black status (i dont think they will match to Black Signature since my uncle got match to Black from EXP and over 25 flights with Lan) Statusmatcher you can write anything, even that you dont have status and you send a nice email and they give you good status (dont use them as source just a reference)
If you do register in the US site it will be more easy to keep your status next year, since on Chile the new rules are crazy.