preping for heavy weather
I would think that going out in heavier conditions than 15 knots would be the next step. The balance of a boat changes dramatically as the winds build and the sails stretch and become more rounded. The 50% jib is probably built of a very heavy and low stretch cloth while your mainsail is built of a lighter fabric made to stand up to normal sailing conditions. As a result the mainsail will power up to disproportionately greater extent as compared to the 50% jib. Steering in waves with heavily reefed sails is also much more difficult. When you are in the troughs there is way less wind than on the crest. As a result you need to develop skills in keeping the boat moving up the back of each wave while blanketed and still be avoid a major knock down on the crest. Low stretch halyards become more important as they are now longer and exposed to greater forces. Being able to properly tension the foot of the sail and properly tension the vang in high winds becomes very critical as well.