Looking at the draft historically from ESPNs draft results:
2017 one DTs went in the 1st, and two went in the 2nd. 8 total went the first 2 days (1st-3rd round).
2016 four DTs went in the 1st, and four went in the 2nd. 12 total went the first 2 days.
2015 two DTs went in the 1st, and two went in the 2nd. 6 total went the first 2 days.
2014 two DTs went in the 1st, and three went in the 2nd. 9 total went in the first 2 days.
2013 four DTs went in the 1st, and two went in the 2nd. 10 total went in the first 2 days.
2012 three DTs went in the 1st, and four went in the 2nd. 11 total went in the first 2 days.
2011 four DTs went in the 1st, and three went in the 2nd. 12 total went in the first 2 days.
2010 five DTs went in the 1st, and five went in the 2nd. 13 total went in the first 2 days.
This averages out to 2.875 1st rounders, 3.125 2nd rounders, and 10.125 Total in rounds 1-3.
So that means if you aren't one of the top 6 DTs, you're are unlikely to be a 1st or 2nd round pick. And if you aren't one of the top 10 DTs, you're more likely to be a 4th rounder or later.
Now for me personally, I'd say neither McIntosh or Norton have a chance to get drafted before Wilkins, Vea, or Payne. So Statistically, the best case scenario, McIntosh will not be a 1st round pick, even in the best case scenario of him being the 4th DT off the board. However I'd say guys like Dre'Mont Jones, Tavon Bryan, Maurice Hurst, and Harrison Phillips all are way more likely to be drafted above McIntosh than not too. So that would mean most likely, McIntosh is looking like the 8th DT off the board. Even then theres still guys like Derrick Nnandi, Rasheem Green, Andrew Brown, Da'Shawn Hand, and Lowell Lotulelei that McIntosh and Norton will be competing with to be drafted above. At least worst case scenario I see Both being drafted - Mcintosh around the 4th round, and Norton around the 6th (again, in a worst case scenario)
Plus if you don't trust me, Matt Miller Doesn't have either Rj McInotsh nor Kendrick Norton in his updated top 10 DTs -
2018 NFL Draft Big Board: Matt Miller'''s Post-Regular-Season Rankings | Bleacher Report