Following this strategy in 2018 you'd buy at 10k, 5k and have another 25% in case it goes to 2,5kUSD but it never did. In this bear market you'd buy at $35k, $17.5k and have another 30% waiting in case it goes around 8.5k.
Good strategy that does not require you to time the market and to find its bottom.
Dollar Cost Averaging is a very good strategy in bear market because if you have belief that bull market will come back, matter is whether you spend whole of your capital for investment into Bitcoin as you wanted. Average price for your investment is important. You can use 50% of capital to buy at $20k, 25% at $15k and 25% at $10k, assume all these prices will be touched in bearish months.
You don't have to stress your eyes and spend lot of time to find market bottom. You don't have to worry to miss its bottom. Maybe your average price will be higher or lower than in perfect case you time in the market, but DCA makes your life more easily.
Yep, this is the way...
DCA is the proven method over time, but I wouldn't even do as big of chunks as you suggested. Put in a little each month, that way you can buy even more if and when the price moves lower.
Myself I don't think the bottom has been hit yet, it will probably go under $18k at some point, but even so DCA is the way.