I just strung a CAP grommeted racquet yesterday and I paid a little more attention to the level of difficulty compared with a regular racquet. I found that it added an additional 10 minutes to a 40 minute "normal" timing.
One important thing is, that I had a special tool that made working with the blocked holes a lot easier. The tool is called a "pathfinder awl" by Gamma (you can buy them from TW separately for about $25). I more or less take this tool for granted since it came with my stringer, but without it I can see DX_Psyho's perspective -- it could have been a real pain to get the string through some of those hidden and blocked holes.
It only takes seconds to work through blocked holes with this tool. This awl is like a normal awl except it has a retractable tip that exposes a tube. So, you can push past any block hole with the awl, pull back the awl tip, and then push the string through the exposed tube (it's an ingenious device!). Without it, I might still be trying to push past those holes. For that reason, I can recommend this tool highly for any stringers that might be facing stringing a cap racquet. I don't think I'd want to face caps without it.