If you provide some additional data I can see what speed it will likely reach before diving without any trim adjustment.  

Divide the hull into 10 blocks of equal length from stem to middle.  Give me the beam at the middle of each block and the submerged volume of each block such that I have volume distribution.  You can approximate the volume based on the height of the sides and half the height of the peak.  Give me the height values rather than volume if it easier.

Also if you have some idea of the height of the CoE above the water that is a valuable input.  Also what displacement?  The total displacement or something a little less?

I will try to get some meaningful charts from my pitching program to show what is happening.  I have attached an image I did based on the 18m proa heading into 3m waves.  I think this was at 50 degrees to the waves. I cannot remember the speed.  It did show that the leading beam would be ploughing, which we now know it does.  There is enough water coming over the beam and onto the deck that it will open the hatches on the lw hull so they are getting some lock down straps.  I did not play with the shading much to get detail on the wave but you can see the immersion on the hulls.  As Rob often points out the lw hull is lifting before the ww hull so the torueing is less on a proa than a cat.  There is not much roll associated with the pitching.

The second image shows the confused wake from the lw hull.  This is at 16kts.  I have not included changes in trim in this one.  It is just the calm water wave train.

Rick