Depends on the variety and the rootstock.

The pictures I have seen shows that the tree's trunk gets thicker as time goes on to old age but the canopy size is limited to a combination of pot size, root branching with a large number of feeder tips and the quality/quantity of fertilizer.

if you were to plant a standard size meyer lemon from seed in a pot and kept it pruned heavy how small could you get it to maintain? and would it survive in containers?

First, any citrus planted from seed would be standard; dwarfing is caused by grafting to a dwarfing or semi-dwarfing rootstock. Second, if you plant a Meyer lemon seed, you likely will not get a Meyer lemon. Third, you would be unlikely to get flowers/fruits for 7-10 years; so would not know what you have until then. If you planted a standard size Meyer (grafted) in a container, you could keep it relatively small depending on the container size and how you prune it.

Thanks for clearing that up, I had it all wrong, but what you said makes perfect sense. So if I were to get a grafted standard size meyer lemon, would it still take 7-10 years to flower? and when you say I could keep it relatively small, could you be more specific? like 6' Tall ish?

It will flower within the first year or 2.

6 feet would be totally realistic; because a Meyer is more of a bush than a "tree". And Steve is correct about the flowers. My recommendation for the rootstock in a container would be Carrizo, relatively easy to find.

I have got a few trees from lemon citrus tree and a few from four winds growers, I've noticed the four wind trees are much more dwarf than the ones from lemon citrus tree, could they be on different rootstocks?

Almost certainly on different rootstocks. Until recently... and maybe they are still using it.. Four winds used almost exclusively Cuban Shaddock; which, at least in containers, produced a semi-dwarf tree.

I have a Fourwinds dwarf New Zealand lemonade tree that sends out an occasional trifoliate leafed suckers. Its sucker level is quite low.

Steve,

Do you know what rootstock it is on?

Cuban Shaddock is certainly not trifoliate.

Four winds will not tell me. They said it was proprietary root stock

where should I look to buy Carrizo Rootstocks?

citrus ree source are my friends; but I don't know if they sell retail

They told me they use troyer and c35 but won't say which on which.

Us897 and flying dragon are the most dwarf rootstocks. You can get trees on 897 from briteleaf and flying dragon from Harris (my hirado buntan is on fd) the just cut the scion off to get trees you can use for rootstock seed.

harris uses kuh carizzo. It's a specific line. I don't know if it's better or worse though. My Xie Shan and dekopon (shiranu) are on kuh.

My Harris Citrus's Meiwa kumquat is on Kuharske Citrange. It is doing well. However that rootstock will be illegal to use or sell in Florida due to its susceptibility to HLB

I wonder if it will still be used for "export"

No But they may have a FIRE BLIGHT sale to clear them out.

My Meyer Lemon is on "Improved" Carrizo, whatever that means, and I had so much trouble getting the leaves to stop being chlorotic. Didn't help that my water has naturally high pH lol. John why do you prefer Carrizo for containers? My White Grapefruit on Volkamer Lemon has had much less problems with chlorosis, always green. However I realize not everyone has alkaline water issues like I do. Both are in containers.