Judging from the dimensions of a smartpot, strawberries are better suited for shallower containers. They grow better in the ground but are easily grown in containers with a depth no more than 12" and at least 8" wide, and plant spacing is determined by how you want to grow them. Personally, I'm trying to grow everbearing strawberries in a window box 6" deep, 7" wide and 3 feet long and will space plants at 6" circles, which is a bit tight but nothing terrible. If you have the space (and assuming you're growing everbearing strawberries.. june-bearing strawberries need more space) then give them a few more inches of breathing room, properly maintained plants will give enough strawberries to make you not worry about wondering if you should've put in more. That being said, a good potting mix with some composted manure/slow-release fertilizer with regular side-dressings of fertilizer (once plants are established) will do you good and give plenty of tasty berries, don't forget to add a black plastic or straw mulch too. Water often, give them a lot of sun, put them somewhere with lots of air flow, and spray them with neem oil or something of the sort if they get attacked by any disease or insects and they'll reward you greatly. I'd also pinch off the first few sets of flowers so your plants can get established and give more, tastier berries in the long run, and cut off runners as well. Sorry for rambling, hope my advice helps :)

Different varieties grow better in each zone. We grow Festival here. I used window boxes for mine. I save the runners because they bear on the runners much better than they do on the old plants.

I'm growing Quinalts. In my experience they are prone to getting a gray moldy something, and need good air flow to prevent it. When I buy new plants they almost always have a few dead, gray moldy leaves in the six pack. I trim them off of course.

As mentioned above, using the 500 gallon smartpot for strawberries is a bit of a waste, as the roots don't need such depth.

I grow them in window boxes, and as underplantings in pots/containers growing fruit trees/bushes, and have not had a problem yet.

I'd space them 6 to 12 inches apart depending on variety, and start by placing the first one 4 inches or so from the border, and circle around the pot, then another circle 6 inches closer to the center, etc.

I've never had any experience with a smartpot, but you could probably cut a bunch 3.5 inch holes spaced 6 inches apart along the sides of smart pot and grow more of them and take better advantage of the depth. You could maybe fit two offset rings worth of additional plants like this, though the ones on the shaded side might not be great.

Post pictures later!

I could always not fill the pot all the way