Kind of late to the party here Sally, but using Eco Print Shield myself, I wanted to share what I have learned.
It has been quite a struggle for me to get it just right. I first bought a quart of the satin, played around a bit, and thought I had something good. I tried different concentrations of dilution and lots of different rolling teqhniques. When I bought a gallon of the matte, things really started to go downhill. The matte really is quite ugly stuff in that it not only dulls the prints, but actually leaves a milky coating. The trick of course was to mix. Wanting to use up the huge gallon jug I had of matte, I bought a quart of gloss. So now I am getting fairly consistent results with mixing 1/2 matte, 1/2 gloss, and to that add 20% distilled water.
Now as for rolling this was a bigger issue. I won't bore you wit the details of how I got here, but this is how I do it. First of all, I have foamboard hanging on the wall. On top of this is a layer of thin brown kraft paper that is actually coated on one side and hence slightly water resistant. On top of this I have tape folded over running along the top edge. The point of doing this is to prevent little hairs and debris from getting on the print. If you have a workshop you might be good, but I was doing all of my rolling on the foamboard that was laying on my carpet, and you can imagine how dust was getting all over the print. The canvas is nicely taped to the kraft paper and just hangs on the wall, waiting for coating.
Now with the coating, I wouldn't say I do anything special to get it on. I actually don't use one of those painter pans for the roller. Instead, my foam roller brush lives in a jar, with the hole to insert the handle pointing up. The jar is always at least 1/2 to 2/3 full of the Eco Print Shield mixture. I do this because washing out the foam is such a waste. This stuff is very expensive so I was looking for a way to make sure 90% of it gets on the print and doesn't go down the drain. I simply slide the metal rod of the handle the foam brush, drag it along the lip of the glass jar as I take it out to remove some excess, and start rolling. Its easy to always dip it back in. I do roll quite a bit, but it is only to put on a thin initial coat. This is of course the coat that soaks up like crazy so I'm always dipping back into the jar, but as I get to the end, i want to make sure I don't have too much left on the brush so that there isn't too much excess on the print. The beauty of my jar is that once I'm done, I just pop the foam roller brush off the rod and put the lid on. It stays dry and always ready for the next coat. I do clean the brush if I was to make another batch, but there really hasn't been any issue with the foam living in the jar as long as its air tight.
Now what I do next is not in the video, but it certainly helped me immensely. I use a dry roller to run over the entire print, over and over again, until all of the bubble have pretty much been worked into the print. I don't push hard, but the action just breaks up the bubbles before they can dry as a bubble. I of course put this roller into a jar too to not dry out in between the coatings and when I done for the day, I will wash it in warm water and let it dry for the next time. Since I've been doing it like this, I haven't had any issues. Sometimes I do get scared when I see the print and can't work it anymore, but after I come back 20 minutes later, its perfect.
Looking at your sample picture makes me think you have actual dry chunks. Someone else suggest straining which is what I will start doing as well because I can see them in the bottom of the jar. I have always wanted to take some pics of my technique and post it so that others can learn from my many many experiments and steep learning curve. Maybe I'll get around to it soon!
Kiran