Personally I'm taking Josi at 40% of the price for a year, and then 80% of the price moving forward for the healthier defenceman that is probably at worst 80% of the production when they're both healthy.
I really would be wary of tying my hands too early in this draft, as McDavid and Drai are not on the cheap side.
Also of note is that I would take the 2021 first rounder instead of the 2020 second. That first rounder is just going to keep growing in value the longer you hold it.