I've been pretty happy with bamboo (~9m Tonkin spars), but have broken and reinforced it.  Still need to try some solid wood or laminated ones (as Hans did for Wakataitea, Klaar did on Ontong Java, and Kiko does in his Hawaiian sprits'ls)...

There is a LOT to optimize in the design and construction of crab claw rigs (and I look forward to a full-on manual), but for now here are my best efforts to lend a hand:

http://econscience.org/tiki/2015/02/15/performance-of-a-bamboo-poly...

http://econscience.org/tiki/2011/04/26/prepping-spars-for-the-big-c...

http://econscience.org/tiki/2011/05/11/rigging-the-13-m2-crab-claw/

http://econscience.org/tiki/2016/05/04/crab-claw-sails-the-mast-to-...

And here's a fledgling attempt at measuring sail dimensions and attachment positions in extant crab claw rigs:

https://docs.google.com/spreadsheets/d/1FHmZAbkyklk6xGKQklI8qAoeJor...

Re alternative masts and the crab claw, Thomas and I had similar thoughts and constructed an A-frame mast on our Hitia 17 with ~13m^2 crab claw (later ~20m^2).  You can see photos of it along with performance data here --

http://www.searunners.net/18-hour-trial-on-lake-wa-nighttime-circum...

Budget Boater said:

Thanks for the link.

I am also (seriously) considering using wishbone masts. I think there are more advantages to this than disadvantages. Wishbone masts will allow the sails to freely rotate. I would need to put a control line on the tack in order to keep it in a stable position, but could dictate that position. By easing the tack control line, I could also quickly move the sails from a "spars up" position, to "spars down" position when needed, with the ability to pull the tack to windward or leeward as necessary.

The added advantage would be redundancy of masts. If something broke, I could modify the rig to single masts until repairs could be made. Will it work? Who knows (Except maybe Gene Perry who did it with carbon fiber masts and spars on his Tiki 26, but I have not heard from him in years.)

Use bip[od masts.  They are infinitely adjustable, put a lot less strain on the vessel, and almost any rig can be used from them.  The Egyptians used it on their reed boats for that reason.  They can be made from aluminium high pressure irrigation tube or other mast scantling.

What one looses in the disturbance of the airflow by the extra mast, one gains in convenience.  Especially useful on a trailer sailor cat.