What games would you be playing? I, for my part, will try to get the highest possible FPS without sacrificing quality, but will compromise on resolution. Especially, on fast paced shooters. Games that won't really allow you to enjoy the benefits of RT and such.^^ At this point any RT use would be an unexpected bonus @ 4K. I fully expect it to be unplayable @ 4K until next gen cards. And even then, who knows. Might take 2 gens.
We’ll see how much, if any, optimization can happen. I probably wouldn’t SLI unless I knew for a fact I could get a solid 50-60FPS with RT. Not dipping into the 40s constantly and such. Might not be possible on the 2000 SLi series. Also, we’ll have see if devs continue to make solid SLi profiles or if it’s support fades more than it already has.
I'm definitely over 1080p, with 1440p @ 100Hz + being what I game mostly on. The exception being flight sims, where a higher refresh rate is not absolutely required.