'least sure' is correct and usable in written English.
You can use it when you want to express something that you feel is the least certain option. For example, "I'm least sure of what I should do next".
Here's where Mr. Connornor's choreography is least sure.
Whether they ever will again, nobody can be the least sure.
What the cardinals are least sure about, by most accounts, is what they want in a Pope, even as there are already factions around various candidates.
Bush advisers seemed least sure of the role in an administration that Mr. Allbaugh would inhabit, although they said it would be an important one.
Worryingly for Labour, and even more so for the Lib Dems, the two parties' supporters are the least sure about their vote.
The former Hearts wing duo of Saulius Mikoliunas and Deividas Cesnauskis are likely to start for Lithuania, with Mikoliunas at least sure of a hot reception from the visiting support.
Yet it was the MPs that seemed the least sure-footed.
Feldman's account is least sure-footed when he tries to root the justices' interpretive theories in their biographies.
Of his recent popular productions — a thrilling "Othello" (with Chiwetel Ejiofor), a side-splitting "Twelfth Night" (with Derek Jacobi) — "Hamlet" has created the most media heat but seems to me the least sure-footed.
The core central-banking doctrine of lending freely though at a penal rate during a financial panic was set out by Walter Bagehot, an early editor of The Economist, in "Lombard Street".Yet despite its venerable pedigree it is the Bank of England that has at times seemed the least sure-footed of the three central banks.
At the very least, make sure your boiler is as efficient as it can be by making sure it has an annual service and safety check.
