Are you talking Korean Giant? If so any other Asian pear would probably work. My issue has always been too much fruit set. KG isn't bad at all to thin. The other Asian's are a royal pain, way too much fruit and all buried in thick leaves. So I usually start by pruning off half the spurs. Then mass whack off buds at the proper stage where the whole bud cluster can be removed. Then still thin fruit by hand.

I think in my conditions, warm sunny days at bloom, these things might even be self fruitful.

Here, even early flowering Euro pears like Seckel pollinate Korean Giant, AKA Olympic. Bradfords probably work as well. All pears are compatible if there is enough overlap in bloom time so certainly all of the Jap or Kor varieties should be compatible. I believe some of the Chinese may flower too early.

Atago has a long flowering season to assure some overlap. From Fowler's nursery site, "Atago has a long and profuse bloom period, making it a good choice as a pollenizer".
I've also read that it's good for cooler climates and the fruit can get exceptionally large. Like 6 lbs+, the record.
I have no experience with the cultivar yet, but have some plants coming in the spring.
But like Hman's posted, there are other options too. I noticed you haven't a zone up top. Where are you?
noogy

I've culled out my Atago tree and grafted those in my nursery to other varieties because it just didn't get the sugar up for me in SE NY. Perhaps it would in a site with dawn to dusk sun here.

I don't think you have to worry too much about what varieties of Asian pears you use for pollination. As Fruitnut suggested the most common problem is over set requiring time consuming thinning. I actually remove almost half the spur wood every year. Here, pollination has never been a problem for me.