Two predictions:
1) No way Moore wins the nomination
2) If by some miracle, Moore is the nominee, he will easily defeat Jones. GOP voters sat out the special in droves because there was only one race on ballot, and who would want to take the time to vote for Moore? But 2020 will be a presidential electorate, Jones doesn't stand a chance.
Remember in 2012, Moore had a close race against Bob Vance, while Romney easily won the state
I would say Lean R with Moore, because Trump is so polarizing, but if Trump underperforms, don’t rule out a Jones victory