cluster craft

whats the best way to craft these two on medium cluster?

Purposeful Harbinger (Mana/Aura tag)

Heraldry

both are prefix

Maybe have a play around with the craft of exile calculator. I'm not an expert at using it, but some results I came up with on a lvl 75 jewel, the odds look better on the minion base than the straight herald base, so I used that, not sure which one you are using:

Trade starting at - 20-30 DIV
Scour alch - 1143 chaos
Trans alt aug regal scour - 1249 chaos
Exalt open prefix - 588 chaos (plus input cost)
Exalt open prefix and suffix - 1114 chaos (plus input cost)
Chaos spam - 4123 chaos
Lucent fossil - 6075 chaos (May be better combination of fossils, but I'm not seeing one at first glance)

Not sure about harvest but that may be an option. Betrayal was an option for doing some cluster jewel crafting, but I'm not sure if you can still input your own on any of the crafts. There may be other ways I have not mentioned.