Hi I got a level 71 Bowazon with full Mavinas, Sanders Riprap, two Cathan Seals and an amulet with resistances. Now what should I socket the set with? I was thinking of a Sheal in the bow and two Ums in the armor and diadem.
Something else to consider would be facets in hat and armor if you're making a magezon or FA zon. Shael's great in armor too if you need to hit a FHR break (I don't think most people care in PvM, but I try to hit something decent).
I'm now considering a Nef rune for the bow for knockback. I've put two Um runes in the armor and diadem for resistances. Together with a prismatic amulet, which I crafted by putting six different perfect gems and an amulet in the cube, I got full resistances.
My suggestions are mainly for a strafer, but they are probably useful for multishot as well.
Strafe/MS bowazons have rather low off-weapon %ed, so it might be a good idea to put %ed/something jewels into the diadem and armor. None with +max/min damage, however, these are bugged in armors. I would not use a socket for fhr, but use charms for that. The set offers 30% and you need just another 2% for the next breakpoint. The one beyond that needs another 20% which isn't that hard to achieve with charms as well.
Regarding the weapon, a strafer needs 10% IAS beyond what the set offers while other bow attacks need another 19%, so if you have an IAS/ed jewel, it might be an excellent option for a strafer (respectively two for a different kind of bowazon). In that case, I suggest a Nef rune in the bow (for knockback). If you don't have these jewels (and neither Cat's Eye nor Highlord's are an option regarding the amulet), you have the agony of choice between Shael and Nef.
Regarding the other gear and assuming that the selection isn't set in stone: The set already adds 15% life leech, so I would use something else than Cathan's Seal rings. I suggest Ravenfrost (CBF is crucial!) and one with resists or even another Ravenfrost. Regarding the amulet, my first choice would be Atma's Scarab (strafers will trigger amp rather quickly, even though there's just a 5% ctc), followed by Cat's Eye and then Highlord's. I would charms to reach 32% fhr, then maximize resists, followed by frw and then perhaps another 20% fhr.