Graduating from the Starboard Blend...2nd board advice?

[XLR8]

I've been riding a Starboard Blend 11'2 for the last two years on Great Lakes surf.  I'm working with a local shaper to come up with the perfect 2nd board.  I'd appreciate taking advantage of some of the wisdom on this site.

I feel I'm surfing the Blend to the best of its potential.  Longboard style surfing in anything from 2-10 foot faces.  Great lakes surf is, of course, close interval swell conditions, wind driven, lots of chop.  I feel the Blend holds me back in anything over a 4-6 foot wave day.  Ive got to work to get a few turns out of the board and it purls in steep conditions over 6 feet.  Some of my issues may be ability-based, but I feel like I am being held back by my gear a bit.

I'm 6'2, 185-190 lbs.  I'm looking for a pure surfing board.  I have other options for other conditions.  I initially wanted to go shorter than 10 feet, maybe 29 wide.  Was thinking a step rail design.  I trust my shaper...he's well known for his surfboards and has been building stand up boards for a few years.  We haven't had a lot of conversation yet though.

I figured at the least you guys could give me some questions to ask or help me put together a sensible priority list.

Thanks a lot in advance.

Rob