Your "strategy" is non-existent. You're simply relying on "greater fools" to keep buying with the intention of selling again for more fiat money, so that you can sell out before they do.
Um, that's pretty much what every single person here is doing even if they won't admit it in public.
It looks like a sound strategy in principle, though that certainty at 1000x returns shows the OP might have been spoilt by past performance. He'd have to be taking risks on stuff that looks like utter junk right now and I think the alt scene has become more established and mature.
2015 was the time to be doing this there were prime contenders that were still nowhere like Monero, XEM and ETH. Back then all alts looked potentially dead, even the ones with good plans and backing. Now a lot of that has come to fruition and the dregs are still where they belong, though no doubt there are some huge risers hiding.
The pulling out half at the doubling is the important bit, everything else will be gravy.