Coat with GlamourII or Clearhield Type C. GlamourII is less smelly and is cheaper (because of dilution), Clearshield probably has better UV protection and does not have to be diluted. If you must spray or roll your coatings indoors, GlamourII is your best pick since it makes the room less inhabitable, but neither coating is really awful smellwise since they are both water based. Don't even consider using solvent based coatings indoors, best to just not choose a canvas that requires solvent coating. Plain glossy GlamourII produces a finish that is closer to Satin than gloss, and is to my eye very attractive. I use it without any Matte mixed in, diluted with 33% to 40% water for either vertical HVLP spraying or horizontal rolling. If you can manage to HVLP spray horizontally, a 45% water dilution will give you the glossiest finish you can get with that material.
The amount of material you need for stretching varies with intent and your stretcher bar width. But it is always more than you would like. To gallery wrap where the canvas is attached to the back of the stretcher bars, you'd better think about 3" on each side for medium width stretcher bars, otherwise you just can't get an adequate grip. If you're going to frame the canvas you can staple to the sides in which case as little as 1" all around is ok, but 1.5" is better once again to get a good grip for stretching. Personally I hate stretching, I glue my canvases to Gatorfoam and can't say enough good things about it. Fact is, a 40"+ printer is the best choice for canvas work that will be stretched.
Those vertical grasses are the real test of canvas texture, and canvases with textures that are more elongated in one direction than the other can fail pretty badly in those cases (IMHO). Well, they may look OK but you and I will know there's more to be seen and it will gradually eat away at our opinion of the print. Also you will probably not see the full extent of the grass details on relatively small prints. I have some extremely high resolution grass field panos and I don't even begin to see the full fineness of texture until I'm printing more than about 200 image pixels per inch of canvas such as a 40" high print on a 8000 pixel high image file. And oh how $weet a print like that is!