I have blades with a 1060, 1070, 2070, and 2080. They all perform pretty much the same for what you're wanting to do.
Do you plan to take this machine to EDC or Ultra where you have (2) 4K outputs and 150 slices? If the answer is no, then a 1060 will get you by just fine.
But, do you plan to sell this in the future? Then getting the latest tech will help your re-sell value. For me, I run my machines until they die.
I own over 15 unit's and haven't had on die yet. They're solid workhorses.
I've ran festivals with (2) 4K out's with 10 slices and about 6-8 layers (not to mention 5-10 active FX) and it never dropped under 45fps with that work load. Not to mention this was out in the 105 degree heat for 12 hours.
whichever way you go, you'll be good.
Currently there's an issue with the new mobile RTX cards and windows 1809 btw. I have Nvidia looking into it and testing Arena with their latest driver updates. Hoping for a fix in the next week. Right now my 2080 get's about 18fps with a single 4K display. It's a windows/Nvidia issue, so it should be fixed pretty soon.
Just thought I'd give you a heads up, in case you go the RTX route.