If that's all that's available, then you have to make do w/what you have. You can add the bonding liquid - I'd say 1/2 or 3/4 the liquid that you use to mix. You can also make your own by using fine sand and cement plus the bonding liquid. If your ready mix has large aggregate, be sure and sift it to get as many of the large rocks out as possible.

slowmedown - thank you very much for your reply.
I will try it on a small Nutec board before I tackle my big fish/mirror panel. I got a nice tip on Internet - you put the adhesive in a zip-lock plastic bag, seal it and cut open one of the corners (opposite the zip) - just like icing a cake! Will definitely try this. Thanks again and enjoy the rest of the weekend!