Frankly, I'm done with counter pressure bottling. It's a total PITA and the results are marginal, at least in my case. I even went so far as to make a totally all stainless CPBF, and the results were still marginal. Mostly in regard to the beer changing in the bottle, not necessarily carbonation. Between loss of hop character in highly hopped beers to perceived oxidation after only a few weeks in the bottle, I was just never happy with the results. I've heard similar stories from others.
My solution? Fill from the tap. No special set up, no special equipment. Put a tube on the end of your faucet so you can fill from the bottom of the bottle up and minimize potential oxidation, sanitize, purge and chill your bottles, turn the pressure way down so you get a nice slow fill. Tap on the filled bottle to generate some foam to fill the last bit of head space, then cap on foam. I've had much better results with this and there is little to no clean up afterward.
I can't explain why this method gives better results for me. With the CPBF I still purged and capped on foam, but for some reason, the act of using that thing just didn't work like it should in theory. If you are planning to make or buy one, try the fill-from-the-tap method first and judge your results. It just might save some time and frustration.