Have big capital with the investment you can increase your BTC.
Seeking for big capital for the purposes of increasing bitcoin in quick time might lead to unwanted results as we might miss to take care many necessary precautions. Always small capital must be good to risk. I have seen many people who are trading with small capital still making decent profits.
If you purely focus on trading, then it doesn't really matter whether or not you go big. Point is that you will always be able to make decent profits in a market as volatile as the one from Bitcoin. However, if you talk about people with deep pockets, then they mostly look for a bit more steadiness when it comes to whatever investment. That's why you see that a lot high level investors take much lower risks for a conservative return. In order to make these conservative gains interesting you definitely need to go big.