@Heirloom
Harrow delight is actually only hardy to zone 5 so we need to rethink that one. Because it was developed at the harrow station in Canada I remembered that pears hardiness incorrectly.
This is a post discussing some newer cultivars Hw623 & hw624 pears scheduled release in 2021
Harrow sweet pollination & description are shown below
https://www.jungseed.com/P/30858/Harrow+Sweet+Standard+Pear
Pollination is always the tricky part as seen here
https://www.acnursery.com/resources/pollination-charts/pear-chart
There are many other good zone 4 pears as seen here at grandpas
https://www.grandpasorchard.com/_ccLib/attachments/pages/GO-Web-Chill+Hours+Chart-PEAR+(2013).pdf
Love this nursery who has many new hardy releases
http://www.cumminsnursery.com/pear.htm
I use my small yellow pear as a pollinator for harrow sweet but I suspect moonglow would overlap it at most locations as well. Moonglow is not a fast grower for me.