Thanks a lot to all commenters in this thread! Yes I do fully custodial storage. And no, I don't have opportunity to avoid private owned exchanges. Like literally on the next corner. The trick is I use to switch countries for that. And last but not the least. So many experienced posters have missed the point. By "clean" I mean that BTC was not involved into criminal based transactions whatsoever. Which is a broken highway even in the case of USA tradeoff from Silkway and German Government after criminal seizures funds.
Conserning the strategy. It looks like straight line up in the perspective of 2010 - 2020 isn't it? So I consider a halving to halving term is sufficient for small bargains to make. Not quite sure about the policy but if you consider the fact that private propety prices have changed gradually from 666666BTC down to 66BTC and not long to wait it to be 6BTC per house. That makes my plan quite reasonable isn't it?