I had same problem
I have a 2004 36 with non-furling main and had same problem. Excessive weather helm and less speed than I had expected. I found that my problem was a poorly tuned rig. My rig was delivered with no bend in the mast. I followed the instructions in the hunter manual for tuning the rig. I now have 6 inches of bend and this has resulted in a marked improvment. Also make sure the halyard and outhaul are tight. Can sail comfortably on a beat without reefing to about 15-16 knots true wind. Can manage to about 18-20 knots true by depowering main by easing traveller, mainsheet, and vang to let the main twist off and spill wind. Find it more comfortabe to put in first reef at about 15-16 knots of true wind. I also added a folding prop which I believe has made a significnant inprovement by reducing drag and improving lift from the rudder due to decreased turbulence. Before the changes my max speed was about 6.5 knots, this weekend we were frequently over 7 knots in 15 knots of wind.