The pitchpole can actually be worse when sailing upwind than downwind.. the reason for this is that as I am sure you know you are never sailing straight into the wind when sailing upwind. the boat is always pointing in at least a 45 degree angle to the wind. therefore the wind is driving into your jib and mainsail even harder when going upwind because it is multiplied by whatever speed your boat is achieving. the upwind pitchpole requires the same remedy... you have to spill some of that air off the jib to reduce the downforce it is causing on the bow.

Usually Trapezing techniques only help if you are sailing solo. when you get more than one person on a 16 and together you are both pretty heavy it only complicates the pitchpole problem because for one the hulls are riding lower in the water and the bows are that much closer to diving, and if you are pitchpoling while flying a hull then you have that much more weight pushing down on the leeward hull even if you both are out on trapeze lines. Pitchpoling is never fully going to be remedied with a Hobie 16 but it can be controlled. it all comes down to how much force is being asserted on that jib.

As an object lesson next time you rig up your boat in moderate to high winds, while on the beach turn your boat up into the wind as you would be facing on an upwind tack. release your main completely but Haul your jib in close on a close traveler. move to the back of the tramp and if the wind is not already lifting the stern of the boat you will be able to lift it yourself with very little effort. This will help you see how much downforce on the bow the jib creates at different reaches and traveler positions. The Jib is absolutely necessary on the 16 in order to achieve the speeds we love so much and to tack in high winds, but the flip side of that is that it pushes those bows deep in the water in the high winds so you have to learn to play with it constantly. Keep at it soon you will get the feel for what the right jib and traveler reaches are for your best sail.