4:1 Cocotek, and 1 part perlite. 

http://shop.fifthseasongardening.com/cocotek-block-gh-5-kg/dp/7976

would that work? 

Pete, I got a brick of this kind to play with.. I saw off some and soaked it, it increase 3x its size and holds water like sponge.   I am experimenting by filling the regular seed starter trays with smaller cuttings and also inside of a container with lid to root some.  it appears that it is too wet.  it is sponge like and I think it is OK to add to the soil,but not sure it can be just it by itself, since perlite adds nothing but air, right? you have to try and report back...

Yeah it will work out good. I use cocotek its great stuff. I actually have used 100% cocotek in a superoots container and it works too. The only thing is you want to add some trace minerals and a little NPK in the mix.

I suggest pre-soaking the coir in a worm compost tea / diluted sea kelp mix, then adding some azomite to it.

I personally like adding in 3/2/1 coir/pine bark/*perlite* correction. However, I have high PH water which I try to offset, figs don't mind PH higher then 7 like some other plants.

I also bought coir to play with and have changed my soil to a 33% coir, 33% small pine bark and 34% compost. I'm having good luck so far. I just don't feel comfortable putting plants into stuff that has no resemblance to dirt. Probably a mind block. I mix in some worm castings for good measure.

Pete,

I'm using the Cocotek in a mix for my first SWC.  My ratio was 6/3/3 (peat/Cocotek/coarse perlite).

Here's a post I did with photos of the Cocotek dry and wet.

http://figs4funforum.websitetoolbox.com/post/my-first-potting-mix-with-coir-6275555