If I was going to spray, the following is what I would do:
https://plantpathology.ca.uky.edu/files/ppfs-fr-t-18.pdf
But, I'm not going to spray. Most of us on this forum focus on disease resistant varieties of apples. Many of us don't live at our farms and some don't get to go to their places but a few times a year. We also recognize that for "wildlife apples" that perfection is not necessary. If we choose the right cultivars and protect them from deer rubbing and rodents gnawing at the bases, we will have everything we need to meet our goals without spraying.
People who sell apples to supermarkets must spray for two reasons. First, the yuppie crowd demand the latest, greatest pathetic cultivars that can't live without life support, and second, because they are abhorred by the least little imperfection in an apple. It wouldn't fit into their perfect little world.
Your Liberty is a good tree that will do just fine without spraying. Your Wolf River was a great apple back when people used to grow it on its own roots. It was prone to fireblight, but it didn't matter that much. The full sized trees looked bad some years but did an excellent job of producing apples. Now that people are growing that apple on dwarfing and semi dwarfing rootstocks, the cultivar can be a real problem in fireblight prone areas. The reduced tree size keeps the tree from effectively dealing with the fireblight like it did in the olden days when grown as a full sized tree.
Your best bet with the WR would be to plant the graft a few inches below grade and hope that the tree roots above the graft and becomes a full sized tree. Or, you could spray it like they do in commercial orchards and probably be okay.
I can tell you that there are very few people who will continue year after year to go to all the trouble necessary to keep puny, pathetic apple cultivars alive and bearing well - unless there is a cash flow of some kind coming in to help justify it. I've seen person after person start out on this route and every single one ends up throwing in the towel after just a few years. If it isn't a business venture, you won't keep doing it.
You will get old - you will get sick - your family members will get sick - your priorities will change - unexpected tragedies will happen - your car will break down - someone will die - a tornado will hit - yes, a host of things will happen, and spraying apple trees will be the last thing in the world that you will be concerned about.
Otherwise, best wishes...and good luck with you apples.