Hi Marty
I purchased the FP-SWB port for my 17-40 and the FP-75B for my 50mm Macro. The 17-40/SWB requires a 33mm extension ring, +2 diopter and a 4CZ63 zoom gear. The FP-75B flat port is also used for the 100mm macro or 50mm with life size converter but with an appropriate extension ring. I'm not sure what extension ring is required as I don't own either the 100mm Macro or the life size converter so I did not ask about it.
Another, but more expensive, option for WA is the FE2 dome port (8 inches vs. 6 for the SWB). The FE2 requires a 50mm ext. ring w/ the 17-40. The FE2 is supposed to be optically superior to the SWB however, when I asked if two pictures were hanging on the wall, one taken with the SWB and the other with the FE2 and all other things remain constant, could you tell a difference? the answer was "probably not". The SWB is $600.00 less expensive and smaller (therefore easier to pack) and was the Subal standard for lenses up to 14mm (on full frame 35mm film SLRs) before the FE2 came out. It will work just fine for the 15mmFE. For me the cost savings and smaller size of the SWB outways the supposed difference in optical quality and when I do buy a 15mmFE, or whatever Canan may come out with for DSLR WA, the SWB will work just fine up to the 35mm equivilant of 15mm. See Stu's pictures above for examples of this as he used the SWB with his borrowed 15mm.
Other tidbits of info that I found out...clearly people think the Subal is the best housing for the 10d (at least for now). The Jonah may be a great housing for a great price someday...but Jonah is a fledgling company that is still working through a number of issues. As far as the Sea and Sea housing is concerned...no one really knows as none/few have been sold. However, if the 10d housing follows in the wake of other Sea and Sea DSLR housings...people, that I talked to, were less than impressed.
Ultimately, for me the disconcern about the Jonah and SS housings wasn't worth the $1000 savings. This is my first venture into a housed SLR, and digital for that matter. I have used film SLRs for years for land photography but never u/w. I don't wan't the experience to be hindered by "faulty equipment". Having said that, I have heard and read about people who were less than pleased with Subal as well. Nowhere near however to the extent that I heard about Jonah and SS. All of what I have learned has been by reading threads on this forum and talking to various dealers. It does not reflect any personal experience and certainly it is not a slam on any particular manufacturer or equipment as it seems none is perfect. It is simply my opinion given the information I was able to glean before making my purchase.
Hope that helps. I will describe my experiences more once my housing arrives. It seems Stu is the only other person on this forum that is using the Subal C10. I'm hoping he will also share his newly gained expertise with us as well.