BTC/USD is at a point where the R/R of shorting has no longer become worth it IMHO. In looking for spots to long BTC I have identified the range of $5150-5450 as my "buy zone". This range represents the Weekly Lows for weeks 10/16/17, 10/23/17, 11/06/17 ; preceding BTC's rise to 20k.
Currently BTC is forming a "Bear Flag" with price at $6,270. I expect BTC to finish the Bear Flag possibly as high as the $6400 Resistance range before breaking down around June 30/July 1 and bouncing off the old diagonal downtrend for the first time since its breakthrough mid April. (diagonals not terribly significant, but confluent none the less)
To address "knife catching" the "buy zone" I have created is built upon the bases of not trying to pick a perfect bottom. There are still "gaps" down to $4475 that could be filled, with HEAVY support starting at around $4875. However during times of capitulation, volume buyers can become impatient and pull the trigger early, before support is reached, leaving some heavy longs out to dry. I personally would rather take a "safer" approach. The plan is to scale in at the top of my range $5450 with 3 orders, the last being the largest and set at the lowest part of my range $5150.
Best of luck