Simrad
If those are the choices, the WP30 or the A4000, then I vote for Simrad. Some of my dockmates with lighter boats than my H37C(18000#) have The Raymarine A4000. They often have to hand steer in tough conditions while my WP30 takes me home. One particularly rough 40 mile crossing from Canada the WP30 handled surfing off waves at 9+ knots. The A4000 owners all turned them off.But your boat is light enough that either should work well. If you like a display and controls at eye level then it has to be the A4000. But you also have the hassle of finding a place for the flux gate. With the Simrad everything is contained in that one little unit. It only needs a ground and 12 volts. If you want wind and/or GPS input then you have to run those wires. If you purchase the WP30 be sure to get the handy remote, you can work at the bow and still miss the crab pots.