I assume Trump is at least a tad higher. I've predicted that this seat will mirror within 1-2 percentage points of the top of the ticket. If the Dem wins, Joni is finished. Nobody is voting D for Pres and Joni for Senate.
I feel like Greenfield MAY outperform the top of the ticket, but again, probably just by 1-2 points max. Looking at 2016, this is about how things played out in Senate seats in Nevada, New Hampshire, North Carolina, Pennsylvania, Wisconsin and Indiana.
I do think it's foolish to try to predict how Iowa will go in November before there's a nominee. There's way too many things that are yet to happen.