A mix of different speakers (one pair conventional and one pair HLCD) is a bad idea. There is a difference in both power handling and output level. So one is going to be under-performing in order to protect the other...or...one is going to dominate the other so that the subordinate speaker is hardly heard. You have to make a decision based on your habits and priorities thereby making and accepting a compromise in some other area.
The JL Audio M770 holds an advantage in near field listening. Warmer. Smoother. Good midbass. The perfect SQ 'at rest' speaker. Plenty of output and projection at surf range. Not enough peak output for projection at wake range, even with four, unless you have an FAE system.
The Bullet HollowPoint is one of the warmer and smoother HLCDs, but it's still an aggressively voiced HLCD, so it places more emphasis on output and projection.
At wake range, comparing one pair of Bullet HollowPoint HLCDs to two pair of JL Audio M770s, slightly favors the two pair M770s in the lower spectrum. Yet one pair of HP 770 HLCDs will deliver a bit more peak output (upper mid/treble) cutting through the noise and distance. Either 7.7" scenario is the minimum required at wake range and pulling without over-driving the speakers.