Thanks, this is great feedback! I'll try to answer what I can here but feel free to reach out if you have any more questions...

I didn't try "update" - I assume that edits the amount you have delegated.

Clicking "update" will just fill in the amount you have already delegated in the "Add/Update Delegation" section so you can then change the amount and update your delegation.

Do you know if it brings it all back and sends the new amount or if it brings back a part of it? I think there would be a difference between the two with the delay or returning SP.

This is one of the most confusing things about delegations. You can only have one delegation to a specific account, so if you have already delegated some and you want to delegate more you have to update that delegation to be the total amount.

So for example, if i have delegated 1,000 SP to utopian-io and i want to delegate 500 more, then i will need to make a delegation of 1,500 SP. This updates my original 1,000 delegation to 1,500.

And one on the "Delegate Max" to warn people that if you delegate the full amount then you won't have any bandwidth to make any actions on the blockchain - but it's a very small add.

The "delegate max" button will delegate the max available minus 6 SP to ensure that your account can still transact. I agree that should probably be better messaged!