Sailing on a friend's C-320 I found the Dutchman's system to be a PIA. This is compounded by insufficient clearance between the bimini and the boom as well as an oversized spring in the rigid boom vang that provides too much support for the boom. Like Rich's experience, it seems like the Dutchman's control line needs to be slacked off considerably to get reasonable sail shape, with the height of the bimini not helping at all.
On my Cal I designed a set of retractable lazyjacks that go up to blocks on the spreaders. The lines were positioned to line up within the ends of each of the four longest of the full battens. Before dousing the main I release the lazyjacks from the mast and tie them off at the boom, leaving enough slack to contain the sail as it is flaked without sagging off the boom. After releasing the halyard clutch I step up to the mast and even out the sail as it comes down. I can then put on the sail ties at my leisure and then bring the lazyjacks back to the mast before putting on the sail cover. It takes more time to explain than to actually do.
On my Cal I designed a set of retractable lazyjacks that go up to blocks on the spreaders. The lines were positioned to line up within the ends of each of the four longest of the full battens. Before dousing the main I release the lazyjacks from the mast and tie them off at the boom, leaving enough slack to contain the sail as it is flaked without sagging off the boom. After releasing the halyard clutch I step up to the mast and even out the sail as it comes down. I can then put on the sail ties at my leisure and then bring the lazyjacks back to the mast before putting on the sail cover. It takes more time to explain than to actually do.