Hi Bill, 

Cabosil is just silica filler like the West Systems 406.  It thickens the epoxy mix and makes it much harder and thicker for bonding and filling.  You can get it under a number of names/distributors.

The Waterline Systems kit comes with a gallon tub of cabosil, a gallon tub of chopped fiberglass, a few yards of biaxial cloth,  some pieces of 1 1/2" thick Penske board (now called Airex PXc board by Baltek), 3 laminated "floor" supports, and the replacement cabin sole cut from teak and holly plywood.  

Penske board and filling in the sump:
The Penske board is used to help quickly fill in the sump by layering this with epoxy/cabosil/chopped glass filler.  It allows you to fill the sump quicker with less epoxy and it is ligher in weight than epoxy.  Jamestown Dirstibutors sells it (http://www.jamestowndistributors.com/userportal/show_product.do?pid=1593&familyName=Baltek+Airex+PXc+Boards) but only in full 4' x 8' sheets.  Not sure who else carries it but be aware of two things: 

  1 - it floats on epoxy so you have to weight it down to encapsulate it or glue it down with a thin layer of epoxy mix then pour more epoxy mix over it to cover.
  2 - cut it using a jigsaw with a 6 tooth per inch wood cutting blade.  The blade will dull quickly due to the fiberglass in the board and wear protection or you will itch big time.

Check out this thread as well.  http://www.j24class.org/IJCAForums/tabid/72/forumid/4/postid/2261/view/topic/Default.aspx  It gives more info and there is a link to Rich Taylor's site showing all the work he did replacing the vermiculite with mixed epoxy.  Someone also mentioned that waterline may sell the kit minus the new sole for $250 but check with them .  They are great people and very helpfull.

Floors/supports:
The floors included in the kit are really meant for reinforcing the keel sump to hull area by tying the hull and keel sump together once they are glassed in place.  By adding wood or plywood strips to the top you can use them to support the new sole.  You can also make additional supports spaced evenly across the hull to fully support the sole.  Check out this pic to see what that this looks like with the sole removed - http://sailaway.homedns.org/main.php?g2_itemId=128&g2_page=3

Last thought on the supports, drill a 3/4" hole through the "floors" at the lowest point to allow any water to drain down to the "sump" area.  Otherwise it all backs up behind the boards and you have to remove the sole to dry everything out.  I found that out the hard way as well.  Kind of like an old wood boat where they drilled "limber holes" in the floors for this same purpose.

Replacing the sole:
As far as cutting out and re-using the existing sole.  It depends on what condition your current sole is in.  Mine was soaked and the balsa in it was rotted out.  You could put your foot through the sole if not carefull (and someone did).  Completely useless so I replaced it.  If yours is dry and in good shape then you just need to add a flange around the cutout to support the old section of the sole.  It depends on how much vermiculite you have to remove. 

If it's just in the sump then don't cut out the sole at all, just do like Rich did and remove it through the existing opening.  If you cut out the old sole but only have issues with the vermiculite in the middle then the new sole can rest on top of the remaining vermiculite and you might not need a flange to support it.  You will have to decide once you get in there.  Just make sure that the keel and hull are fully supported before you start because once you remove the vermiculte there will be no support for the keel except the fiberglass banding around the keel and stub.

Good luck and don't hesitate to ask if you have any questions.
Steve