Got some pics of the tree? What size is the base? Pics of major branches would be good too. I will be doing my 1st topworking this year. Younger stuff though.
Thinking you shouldn't do stuff much larger than a coke can in size. You also shouldn't loose too much of a mature tree. Do a few major branches each or every other year. Wide bloom time or similar bloom times. I like to stick to bloom group 3 or 4 in general, but made an exception to liberty because it was such a good tree. Liberty is bloom group 2.
Dolgo, kerr, or chestnut would be easy to get from someone on here. could even put some liberty on there if you'd like. I am topworking my golden delicious because I don't want to deal with CAR if possible. I also cn't shoot deer in any spot in my backyard. Where golden delicous is a prime spot where deer show up and a safe place to shoot as well. However, golden delicious is a common tree planted in orchards to help other trees bloom.
From what I know upper branches are better for topworking than lower. You also need to time this well. You want to do this right before the tree wakes up. Put it on there too early and hte scions die up and die, and cold damage is a factor too. Lower branches don't grow as vigorously. However, Those sap suckers can be used to "park" scions for a year. or two. Got ides of march, AWHO, and dabinet parked on a tree or two.
Got a nice n sharp handsaw? Also need some grafting tape and something to seal and cap off the cut branch with. toilet bowl wax rings are commnonly used. Some folks have used latex paint too.
An orchard ladder is a great buy to get. Much safer than a regular ladder. If using a regular ladder tie it off hald way up and toards the top too. Use a good sized piece of wood to level the laddrer too.