Hmm, you’ll notice now that everyone (myself included) is donning a Five Hammer (upgrade irrelevant) with 5 slots open filled with Lv5/6/7 Red Gems (roasted). Lv6 being the average you’ll see. Red Gems on main-hand weapons increase Max Attack (this includes magic).
This is a good weapon until you hit Lv317+, where you’d get a chance at a Practonium, which you can then use to create either a Windia Rod or a Vienarasis Mace. Most people go for the Mace as it’s easy to trade out once you’re done with it (it has a lot of INT and magic attack). Don’t bother upgrading or transcending it, just put the mandatory Lv6 or higher Red Gem in it. If you don’t intend on going for Heart of Glory (rod / needs 2 pcs Practonium), then go for a Windia Rod and upgrade it to +5 at the earliest, then socket Lv6+ Blue Gems and Transcend it to Stage 3+ as soon as possible.
Offhand is purely preference. Most people I see now have the Pajoritas Dagger equipped (can go up to 2 slots but 1 slot is fine since’ you’re using Magic for DPS).