The Lowes garbage blocks are designed for people who think trees need to be blockaded in with little tree rings. They're not really designed for significant retention or structure. I wouldn't feel great about it. Do you have stone yards in the area that sell pavers and retaining wall block? I assume that's also where you'd be getting your pavers. There are some "economy" brands of interlocking wall block, and I'm seeing that the smarter yards are now selling wall block by the piece for smaller projects. If you're using CMUs (technical term for cinderblocks), you need to dig a footer to frost depth, pour a 4-8" footer depending on specifics, and then build your wall with the CMUs, using mortar and rebar. If you attempt to just dry stack them on a gravel base, there's nothing holding them together. You'll create a failure point for your patio. I spend my life in a lot of backyards, and where a patio rests on, or is supported by, a retaining wall - that's a common failure point. Overbuild it. Trust me.

Cover holes are typically too close to a pool's edge to allow fun things like walk by someone, vacuuming and other pole work, etc... just as my friend, golfgeek has mentioned. Fence hole placement is a much tighter tolerance requirement. A safety cover's hole may be placed a couple inches in any direction from the ideal spot as well as permitting the hole to be slightly less than vertical where fences not only must be placed at a specific distance, but usually must be perfectly vertical. Additionally, when using Baby-Loc with fiberglass poles, a slight lean in or out may be appropriate on curves. To do this properly, a core drill and torpedo level are needed to get the angle desired and the feet of the drill stand all making contact with the deck. This is a time consuming task, especially with paver decks or stamped concrete, where the deck level is different every time you move the drill stand. Drill stands have bolts for feet that get adjusted. Grass is a real PITA to get right and is not, IMHO, a real good surface for a removable fence to be set on. There is a lot more installer skill needed for the fence to be done correctly than for a cover. Fences depend on tension and gentle curves for strength and appearance. A sloppy fence will have waves or be too hard to connect each section to the next. There I go again, rambling on. Sorry. Scott

KOH and NHBabs, thanks for your comments. I'm attaching a picture of the existing backyard. You can see the rock path curving around and meeting the patio to the right. The concrete extends in a walkway from that patio to the back gate and past the back door, out to the driveway. To the extreme left is the carport and garage, which form the side boundary of the yard. As for the use of the patio, there will be a pergola covering it (denoted in blue), and a hot tub and a place to put two chairs and a small propane fire pit. Not much scooting back and forth of chairs will be going on. (The grill and trampoline pictured will be relocated.) Here is a ROUGH diagram of what I've been playing with... slightly altering the stone path and the bed that it confines to extend out and over to a poured-in-place paver patio with the same crushed granite between the pavers. I've been playing around with lots of different iterations. I think I'd probably have less of a curve downward with the rock/gravel path and make it wider where it meets the patio so that it forms a more organic shape. The thing I can't rectify in my mind is the juxtaposition of rectangular concrete and natural stone. Since I have a rectangular concrete patio already, and don't want to have to resurface it, I'd like to marry the two types of surfaces. I'm just not sure if I'm approaching it the best way.

It's hard to tell, but it looks like a "vee" slope between the house and fence, and quite steep for pavers in that skinny width. So if that is the case and you were to follow that "vee" shape, the pavers would need to be smaller/skinnier and the pattern may affect how much lippage you get (depending on orientation). I see the one drain in the middle, but don't know if the grade is slope towards it (front to back direction). I don't understand your description of how you will use plastic vs 'fabric liner" either. Is the house a slab foundation, maybe California? To accomplish a standard interlocking paver install, you would need a depth of 4"+1"+2 3/8" min, and it doesn't look like you can achieve that with the current grade elevation, so digging and hauloff would need to occur.