5'10", 180 Lbs... More like average. How do you figure out the right length? What makes a short one hard to ride?
Balance & Stability. Think of a see-saw, the longer it is, the smoother the balance is, more room to distribute weight. The shorter it is, the transition is more abrupt.
But the upside is you get more response, more tossability. But thats only useful if want a hull that can perform manuevers that benefit from less length in the water.
Given that many of the hulls being made utilize factory SJ or equivalent ride plates, and since we're talking about length.....
There are a handful of hulls being made that come with very long composite ride plates that you can cut down. But these skis IMO lean towards freestlye more than freeride. So it really depends on what you want spend your time doing.
This is my ride plate
This shows how long it was when I received it.
Here are the skis that offer ride plates like this:
Footrocket
Backie Chan
Aquabot
I want to say there are more but my brain is failing me.
Anyhow, the key IMO on these skis is buying a spare ride plate
with your hull. You can establish how short you want to go, and you still have a spare. The spare can be used to keep full length for surf, or you can shorten it if you think you went to far on the first one.
Weather you are interested in that or not, the best news is that there are a lot of great hulls being developed and built right now, here in the states and abroad.
It'll be interesting to see what you choose.