hehe :lol: I'm feeling kind of dense too that I'm not getting my point across!!
Let me try once more....
I have the Boye Interchangeable set. All needle points are 4", same as what you are talking about. The shortest cable length in the kit is 12", which when used with the needle points makes a 20" total length circular needle. I think we are in agreement with that.
Now, when I use that combination (ie. the 20" total length needle), the cable is almost too short when the needles are in use for the needle tips to meet to make the stitches properly. Do you know what I mean there??
So if using a 8" cable, such as you have made for yourself, which makes a 16" total length circular needle, I can't see how there would be enough leeway for the needle tips to meet in order to knit properly. Obviously, only the cable portion of the needle is flexible, which is why I brought up shorter length needle tips. No, you can't buy any different length needle tip for the Boye set, only the 4" length that it comes with, but I have seen shorter circular needles in stores (like for instance, a 12" total length circular needle) but they have MUCH shorter needle tips in order to allow for enough flexibility to knit properly with them.
Now do you know what I mean???