"1t1v is like a 1a1v where every account has only 1 SP."
I don't even understand this analogy. 1t1v allows you to distribute your stake as witness votes as you will, but to only vote each SP once. If you have more than one witness you want to vote for, you can split your SP however you want. It's nothing like 1a1v, which only allows one account per user to vote, no matter if your other accounts have SP.
If every account on Steem only has 1 SP. Then 1t1v == 1a1v. This allows maximum flexibility to allocate stake to votes. This is the assumption I work with.
Not at all, because I can vote that one SP in fragments on 30, 50, or 100 witnesses. To vote 100 witnesses with 1 SP I'd just vote at 1% VP.
What 1t1v really is, is just 100% depletion of VP. Then each SP you vote is depleted of VP, and cannot be voted again.
That's 1t1v.