I don't get you. Based on what I understood you're planning to borrow fiat once you've got enough bitcoin. Does this mean you're planning to borrow money placing bitcoin as the collateral. For borrowed money you need to pay regular interest.
Maybe this can turn to be effective, if the borrowed money is invested on something that brings you regular income.
The OP only means how he will make profit, and hence sharing us his ultimate strategy to make money.
BTW op you mentioned that if you sell your Bitcoins, then you need to pay tax for it. But I would say why to sell your Bitcoins at exchanges? Do P2P trade and save money from taxes.
Moreover the plan is great to listen, but risky to execute.
Nevertheless, OP if you ever successfully complete this strategy of yours, then do let us know here in this thread.
We are waiting for you to get rich.