I can only comment on the Spring Run. That was my first stripper (not quite finished yet but usable). I am the same hight/weight/foot size you are and I have lots of room in the Spring Run. My next kayak will be smaller.
The type of strong back Joe uses works great. It is an "external" strong back. Very stable and you don't have to worry about it warpping.
I have never used an internal strong back so I cannot give a comparison.
The seat: First of all, it is VERY light. Second, you can buy the foam from Joe (the best I've seen), and carve your own.
I'm sure there will be many more posts for you to read through.

Jim Horlacher

: I was torn between two of the most beautiful yaks out there. The Guillemot
: and the Spring Run. I think Ive settled on the SR, but I like way Nick
: builds the Guillemot in his book. Does the SR plans show the same
: strongback type of method? If not how difficult would it be to put the
: forms on a strong back?

: From what I have read on this board the SR is very similar but more stable
: than the Guillemot, true? Will it fit my big feet? (11's) I am 6'2"
: and 180#, Im not too big am I?

: Has anyone actually used the seat that Redfish kayaks makes? Is it as comfy
: as it looks? Is it as heavy as it looks?
: I know, lots of questions, but I am still kinda torn. Ive read Nick's book
: and I seem to know how to build the Guillemot, I just dont know how Joe
: builds his Spring Run.

: This will be my first home built, I dont want to make a mistake in choosing
: which project. I may not be able to build another one right away as I have
: a 10 month old daughter who doesn't appreciate the feel of a plane slicing
: through cedar.

: Thanks allot!
: Andy