Downwind Catamaran Sailing

[krafthaus]

Question on sailing a Lagoon 400 (or other cats) downwind.

The Lagoon 400 manual has a section with sail trim guidelines in their owner's manual for various points of sail.

On downwind sailing it says never sail with just the jib/genoa only above a certain wind speed, and must have mainsail up anywhere between full and 2nd reef as minimum, again given certain wind speeds. (I looked for the manual online to post the details, but sorry, can't locate it.)

This is related to stability of the mast/rig and potential for damage in strong winds which I take is due to mainstays off the sides of the boat as opposed to a backstay typical of monohulls.

Manual also says not to sail directly downwind, and it recommends 30 degrees off the stern (or perhaps it was 15?). This is due to faster sailing on this point of sail I take it as VMG is better than straight downwind sailing? This is ok if you are on a larger open area of water, but not a narrower channel between islands for example, as you'd be gybing back & forth. If straight downwind is not recommended for rig stability reasons then how does a person gybe (rhetorical question)? Can't sail wing on wing either?

Anyway, I would appreciate comments from those with more knowledge and experience on this subject so I understand the reasons, risks, concerns. Thanks All.