If it were up to me I would give him a season long contract, on pay parity with what we would pay a top level proven manager, he has earned that.
Any extension would be performance dependant of course. Top top results would earn a larger extension.
Ultimately, based on pedigree, Carrick doesn't have it, he has done pretty well at Middleborough, and a really good half season at United considering what he took over.
Managing United is one of the greatest accolades in football, getting a permanent contract likely is (and should be) viewed by Carrick as beyond his wildest dreams given his managerial experience.
I appreciate his/his teams negotiation stand point will be well if United see Carrick as the right person to appoint then we expect him to get a contract reflecting that, but United should be firm on contract length. We have squandered tens of millions on sacking managers, the last one Amorim was in my opinion trying to be sacked for the payout, and we prematurely gave Ole a lengthy contract.