There's no difference using zip ties vs. hog rings in terms of the "finish." You do need to turn the cut zip tie end downward. They're probably strong enough, but I haven't used them for any length of time, so I don't know for sure. They might squeak a little, the nylon against the metal, so a dab of superlube, syl-glid, or maybe just silicone spray might be in order. I noticed a squeak after the switch that I hadn't noticed before, but maybe it was there before...
Also, fyi, my foam was cracking in the crease between the bottom rest and the bolster, mainly on the driver side. I used Gorilla glue and it worked great. I sprayed the crack with some water, lightly, and then smeared some Gorilla glue in the crack - not TOO much (it kind of disappears and you want to put more on, but that's not necessary). The GG expands a bit, solid adhesion...