How much weight will you have on the rail and what is the period of the swell? Long period may be ok with the higher wind. If the chop is short, you'll do a lot of pounding that will slow you down. The key is to keep powered up to drive through the chop. This may dictate different head sails for the conditions.
Major variable is if those forecasted conditions turn out to be anything near reality and for how long will they affect you. If you're on the edge of a decision ... sail in the middle to see if one or the other works best.
Another problem is with higher waves at night you end up sailing by feel as you really have trouble not being able to see the variation in larger waves. So what might work for you during the day ... may not work in the dark.
Have fun. attached photo summarizes what night racing is all about.
Thanks for the advice everyone. We ended up with a forecast of 4'-6' seas and 15kts-20kts wind, with a forecast shift of 90 degrees over night.
If the seas were not too bad, the higher wind offshore looked very appealing, so we ended up heading offshore planning to tack back in if things were too rough.
The boat seemed to be handling everything fine so we stayed on that tack, cracking of a bit for speed when the shift came. The crew mostly handled things well (a bit of time was spent on the leeward lifelines, including yours truly...)
The 90 degree shift came just as expected bringing us back inshore on the same tack!
A lot of people in our fleet stayed inshore and the shift really messed them up, so we were able to carry the day!