if the miner is not your best friend or relative, then he will not be interested. a miner with the power to mine a block with a 100% probability earns more per month than in all puzzle wallets.
There is no need for 100% probability. The miner just has to include the transaction in the candidate block manually and mine along with the other transactions from the mempool just as normal. If he wins, broadcast and it will get confirmations, no danger for the attack any more. If he not wins the block, no problem, just try again with the next block. Just never broadcast the transaction to other nodes mempool until its mined.
I would think a high fee for this semi-manual service (say 1 BTC) might be enough incentive?
Am I missing something here?