I think yo do not understand what are you talking...
Clearly you're looking to fool people who don't, sadly for you I'm not one of them.
Give me public key what ever you whant and give me start private key with whom I can find public key for 1 day with speed 1Ph/s
This is exactly the same as what you offered above-- you just offset the starting position of the interior step.
In what you describe, I choose x and y so that their difference is 60-ish bits. Then I give you y and xG. You would compute yG - xG and begin adding steps of the table_size to it and looking up the result in the table. Once you find a hit, you add the table position, the loop offset, and the y value to yield x.
What I described to you -- finding a private key whos pubkey begins with a long fixed string is an actual test of performance.