DuraCeramic or Ovations:
Either way, grouting with Congoleum's acrylic grout is a chore. It cannot be grouted like you would with ceramic.
The acrylic grout tends to dry on the surface of the tiles rather quickly, so you will need to grout small sections (such as the joints around 1-2 tiles at a time) and immediately clean with your grout sponges.
The goal here is to keep from scrubbing the grout and haze off these tiles later. If you can find a large cellulose sponge (similar to the one in your kitchen sink, but the size of a grout sponge), this will help the cleanup process.
Do NOT spread the grout over the entire surface of the tiles. Just concentrate on the joints.
I use an epoxy grout float, but any will work. Keep 2 grout sponges in a 5 gallon bucket of water (fill it about 1/2 - 2/3 full). Two bucket will save a little time. Try not to get excess water in ungrouted joints.
After you have grouted a few joints,scrape excess grout off the tiles and scrape back into the grout bucket, set the lid on the top of the bucket and your float on the lid. (if you leave the top off for long, the grout will start to harden and you will get chunks of hardened grout in your joints later, and it will not look all that great). Wring 2/3 of the water out of a sponge and get to wiping. When it seems you are just smearing the grout and the sponge isn't picking any more up, flip it over and continue wiping.
Continue until you have gone over the newly grouted area once this way. Place sponge in the bucket and grab the other sponge (the large cellulose one we read about earlier, if available). Wring as much water out of this sponge and wipe across your grout joints at an angle, so you do not dig grout out of the joints. One side of the sponge, one swipe, flip, one swipe. Rinse well. Again, wring out well. one side: one swipe, flip, repeat. You want this area well cleaned with minimal haze on the tiles.
It save a great deal of time if you have someone helping you with the cleaning/rinsing and wringing of your sponges. Change the water in your bucket often.