Sailing one-up, you would have to leave the jib on the beach to be true to your Portsmouth rating. If you put the jib on you would be exposed to an adjustment of your rating.

You sound as if you are unsure where your mast was raked last year. I think that would be the first thing to look at regarding your helm. Also look at your rudders, do you have the port and starboard rudders installed correctly? Are you getting them pulled down completely?