Drop a tooth on the sprocket and give it a try. Important thing with big gears is to keep a lid on it going up hill, however hard it feels. And stay in the saddle.
How steep? Unless you're going less than 16/17mph I reckon you're better off in saddle, but there's not much in the way of steep hills on the TT courses round this way (that I ride, anyway).
Drop a tooth on the sprocket and give it a try. Important thing with big gears is to keep a lid on it going up hill, however hard it feels. And stay in the saddle.