Any suggestions for growing Apple rootstock?

I want to try to grow some apple rootstock but I am Not sure what type of apple seeds to use. I do not have access to many different kinds of apples other than supermarket varieties. Does anyone know if any of the supermarket varieties make good rootstock? Something that is disease resistant. I know I can order pretty much anything online but I wanted to see if I could grow it myself. I have done some research on rootstock in all of the numbers and codes like G 41 and M111 seem fairly confusing to me. What variety apples are those? I do have an apple tree in my yard now. Is it possible or better to take a cutting from that and try to root it? I am Not sure what variety Apple it is but the tree is fairly old and is quite large. Thank you for any suggestions. I also have another post on here where I was trying to identify a potential disease on a tree if you happen to see that also.

https://permies.com/t/52830/apple-trees/identifying-wrong-tree

Without knowing where you are (your climate), it is difficult to give advice re root stock.

Those mysterious numbers that the various root stocks use identify each variety, and its strengths/weaknesses.
They identify varying stages of dwarfing, hardiness, etc.
Selecting the 'proper' rootstock is determined by factors such as tree size desired, climate (heat/cold & wet/dry), soil type, disease resistance and other factors.

Many of the dwarf varieties require staking, as most have a lesser root system than 'standard' stock.
If you are in a cold region (Zone 5 or colder), dwarfing stock is not recommended.

As far as supermarket apples for root stock, the two most commonly used are Red Delicious, and Fuji.

As far as climate and location, I am in northern New Jersey. Thank you for the suggestion of Red Delicious and Fuji. Have you tried either or have any experience with growing from seed (rootstock)?

I'm in Colorado. went to local whole foods organic market (figured they got some local varieties) dried some seeds- then planted. now have a 2.5 yr old tree and it's about 4 ft. high and ready to cut to make it a dwarf next spring bc. CO> get strong winds and dwarf trees have just as many apples I understand. and take less water etc. use cut off water jugs with earth packed deep and high all around them to over winter the year and 2 year old trees. I keep about 5 inches at top for sun and to water them on warmer days....when they pout grown the bottle. I cover with some bird seed bags to keep sleet and freeze off them. so far great.

When you talk about the water jugs with dirt in them, are you talking about sprouting the seeds in water jugs and using them as planters?