Hi,
I know what you mean, exactly ;) That waterblock picture was not from the final installation. It was just there, well, for the show off :) Anyhow, yes, barbs are protruding slightly (on the cooper side) and they are not affecting the flow BUT more importantly it's fixable if you are pedantic (like me). Take a look at this picture:
http://62.204.32.7:10973/X1900/x1900_bits.jpg
You will get this with the EK-FCX1900 and you may ignore my DD G1/4 PerfectSeal barb on the left. Notice the two metal "washers", on the bottom/right. I used them in order to move slightly back the thread part from EK barbs (for the perfect fit), by placing this between the barb and the water inlet (cooper side). Also, DON'T remove the washer from the EK barb when you are doing this, as otherwise connection will leak. Here is the final installation:
http://62.204.32.7:10973/X1900/x1900_barbs.jpg
You see what I mean :cool: Plexi side is not a problem as it's deep enough. Also, as shown in the picture, this is my preferred set-up for single card version (if you have crossfire prepared block). You may notice the white stuff inside of the block, where the threads are. That's PTFE tape on the barbs/caps threads. I like to be on the safe side, apart from the fact that caps/barbs do have the o-ring seal.
Which DD high flow-barbs did you used ? Please note that threads are G1/4 BSPP straight and you have to use the appropriate barbs. Block is coming with nice EK barbs and DD PerfectSeal G1/4 barb (as shown in the picture above) is also nice option. Threads on DD are slightly shorter, which is good.