Rationale:
1. You will (over time) benefit from the daily fluctuations in price
2. Assuming the buys are made on an exchange the only fees will be the exchange fees for each buy - these are likely to be on a percentage basis and therefore indifferent to one $1400 buy or seven $200 ones;
3. withdrawals to your wallet can be done weekly or monthly as you prefer to minimise network transaction fees
If you do Dollar Cost Averaging, you won't care too much about fluctuation.
Of course you do - its the whole point of buying on a DCA basis: you recognise that the price varies up and down (i.e.
fluctuates) and so you spread your buys in order that sometimes you benefit from buying at a lower price. If you didn't care about fluctuations in price you may as well just use your entire investment in one go and not bother to cost average.
There are two scenarios for DCA. One is when you have a lump sum of money to invest, and the other is how to invest your income over time.
Lump Sum ScenarioIn the lump sum scenario, it can be shown that investing the lump sum at one time is the best strategy (on average). Of course, your return will vary depending on what happens after investment, and DCA would reduce that variance. However, DCA in this scenario has an opportunity cost which can easily outweigh that benefit.
Imagine that you invest portions of a lump sum over a year. You expect the price to increase over time, so consider how much more return you would have at the end of the year had if you didn't wait a whole year before investing those last portions.
Investing IncomeIf you have an income, the idea of DCA is to automatically invest a fixed portion of that income when you receive it. This encourages you to save and it eliminates the temptation of timing market. It is the superior strategy.