I find the easiest way is this:
-place yourself between board and sail (with the mast on your side)
-one hand on the mast (near the boom)
-one hand on the board (between front and back straps)
-don't climb, but jump/vault almost a la Bubka feet first
near the mast base
This sounds hard, but in the water it's the fastest way, not much effort
is needed (if you're that tired stay on the beach anyway ;-) and
you're right away ready to uphaul. No hook contact.
About waterstarting, you're right: it's the best way. If there's enough
wind to use the harness, there's enough wind to waterstart.
I think some people think waterstarting is an advanced high-wind trick;
instead, it's the key to happy sailing and should be one of the first things
to learn (ages before trying jibes and harnesses). Just my opinion.