You should definitely look for a pointed nose, it will be more pleasant for flat water, especially with some chop.
Look for "fitness" boards that are like the 12'6" racing boards but smaller (for easier handling and storage) and often stabler. They are typically around 10'6' - 11'
Or the "Hybrids" that are somewhat a crossover between a surf shape and a flat water shape.
- Nah Skwell has the fitness line
http://www.nahskwell-sup.com/fitness/- PSH had the hull paddlers (I guess not made anymore)
- Bic has the "cross"
/0.jpg
- Gong (not available out of France) has the "Perv"

- etc... I think other brands also have this sort of crossover board combining the comptacness and stability (wide nose) of a surf shape and the efficiency of flat water hulls