Would a Harbinger be able to use it well? Otoh, they have such high phase lance DPS that it almost doesn't matter if its soft or not, and the range cut puts it in more danger. Plus, OP cost.
I have tried it, it is quite interesting to play around with however there are some problems that arise compared to Adv. Optics + Phase Lances.
DPS is significantly higher since 6x timeflow (with Phase Anchor) * 110% damage (115% S-mod) = 660% standard DPS (690% DPS S-mod), it's quite noticeable with the way modifiers stack (Entropy Amplifier and Target Analysis buffs are massive with HSA since they seem to stack multiplicatively) and you will one burst a lot more ships consistently even with defensive skills.
Main problem here is range : max range of HSA Phase Lances is 540 (400 after range reduction +15% from Gunnery Implants and +20% from ITU), the maximum range of Adv. Optics Phase Lances on Harbingers is 1010 (1250 with maximum Escort Package bonus of +40%). This is very important since what makes Phase Lance Harbingers so strong is great DPS and good speed with range - you can dodge most hits coming your way by the time phase cloak can be used again. Instant travel time also helps a lot with precision shooting sections at range (like deliberately targeting problematic weapon mounts or engines)
It depends on matchups, but a lot of scary things like Devastators, Chainguns and torpedoes are avoidable at 1000 range, but not so much at 500. But if you're fighting Luddic Church and Tri-Tachyon most of their high burst damage is avoidable.