Big board + efficient strokes! Combination of the two can make for great fun if you enjoy mowing the lawn! May not be up to the level of kite loops but looping after a turn or to start can be a great way of gaining momentum.
8-9 knots on a 10M today on a 146 UG Stella going upwind @ 65kg. Just need to be efficient with your strokes and make sure you let the kite breathe! If it wont do the upstroke without stalling, then try trimming the kite slightly. If it wont stay in the air, give it up!