The issue is what you mean by "not enough" apples. Your aim should be the amount of apples that's best for the tree, in the long run, not maximizing your yield in the first year of real bearing.

If you save 60 and half are left, that would seem about right to me for a tree the size of yours.

My Fuji is fruiting for the first time this year, not yet the size of yours. I've saved about 3 dozen, hoping for half that, but I'm not sure I should have kept quite so many.

I thin, but not right away as some of the small apples will fall off by themselves. I find my Apples 'self-edit' quite well. Also there is 'June drop' where you will find up to twenty small apples on the ground that really did not pollinate properly. Then there is the 'KING' apple to look for in a cluster (simply means the largest of the bunch!). Many just leave on the king apple and pinch off the others. I happen to be a bit more greedy and leave at leave two on. There are many varying opinions, this was simply mine. Mrs. G

A healthy 15' foot tree can handle a lot more than 60 apples. I don't care how many it had last year.

The tree seems vigorous and mature enough to just thin to decent spacing. I would do it as soon as the apples have fattened out enough to know they are set- usually by 10 days after petal fall.

I am going to thin my Goldrush trees today. Goldrush usually has a clear king in the center of the cluster once it is ready to thin and you can safely remove all other apples in the cluster if you protect the tree adequately- if you fear insect damage leave a couple apples per cluster. Remove all the apples from clusters where they are less than 4" from another one- this is what most assures a crop next year, IMO. Those empty spurs will produce fruit next year.

Come back in 2 or 3 weeks and finish the job to one fruit every 6-8"- you will likely find more apples than there should be given how well you thought you thinned previously. The fruit elves are always sticking back fruit in the night. Not sure if they pick up discarded fruit from the ground or just use elf magic to make new ones appear out of thin air. Someone should do a study.

Thanks, so is it okay to spray Immunox right after thinning?

Also, when you talk about insect pests, I do not plan to spray anything else. I was under the impression GoldRush is one of the varieties one can grow without much intervention. Am I assuming wrongly? (I live very near you, Harvestman, in the Hudson River valley.)

Yes, Goldrush seems to often produce usable fruit without spray in our area if you don't mind intense sooty blotch. I have not tested this thoroughly, by any means, but have noticed that it is one variety that in my nursery holds decent fruit on seasons I haven't applied insecticide. Fuji and Winesap as well, so it probably has something to do with hardness and lateness of apples.