I've only been playing for a few months, but here's what I've seen from similar katana braver searches:
First off, great news, next week (starting the 23rd) will be an Affix Boost Week where you'll get an extra +10% chance of success on all affixes! This means that you can upslot to 6-slots with 100% success using a 40% Augmentation Aid (100 Ex-cubes) and affixes that are 100% before upslotting
General rules of thumb:
- Mel and PP are king for us, but fitting in at least some HP becomes more important on units in Ep 5 & 6
- Someone suggested between 900 - 1200 HP for Eps 1-4 and 1200 - 1500 HP for Ep 5 & early 6. However, this was class-neutral advice so I'd adjust based on your subclass and how comfortable you are dodging/countering.
- I've seen 100+ Mel power as a goal for units, but I think that's usually in reference to 4-slot units.
As for the new content, I don't know what's coming but people talk as if most of our current affixes will be outclassed in the eventual endgame (S-grade affixes were announced for Ep 5 and at some point I hear units get SAFs like weapons have now)...
- I've seen people that are preparing for endgame talk about only making 4-slot units because that's the maximum level for which you can buy "insurance" from the swap shop (i.e. get all your fodder back if Dudu fails you, as is tradition).
- Also keep in mind that it costs 25 transfer passes to move a 6-slot but only 5 transfer passes to move a 4-slot. And apparently there's a way to use the transfer system to upslot with 100% success by adding ability augment items (e.g. Noble Might) as you go, but I haven't wrapped my head around it yet. Here's a reddit post though: https://www.reddit.com/r/PSO2/comments/fw3nqj/getting_the_most_out_of_your_ability_transfer/
At the moment, I believe the high-end stuff to go for is Aether (Ether?) Factor and Astral Soul. And then the other 2 slots are something like Doom Break 3 and Veteran's Resolve 5. However, I hear you want a heck of a lot of meseta (~100+M) to attempt all of that. Another reddit post from today with some affixing suggestions you might find interesting: https://www.reddit.com/r/PSO2/comments/iv479l/affixing_ideas_and_recipes_for_dudu_week/
As an example of the endgame struggle, Aether Factor requires 4 copies of "Factor Catalyst" as well as 1 copy of "Aether Soul" and none of these drop in the wild. Factor catalysts come from combining Deus Factor + Mother Factor + Yamato Factor and Aether Soul comes from combining Eastern Soul + Full Vegas Soul + Escarde Soul. But the real fun is that I believe the chance of success is only 10% for both, so next week you could get it up to 60% with the boost plus a 40% augmentation aid item, "That's a lotta Ex-cubes!"
My recommendation would be to go with a middle-of-the-road 5 or 6-slot affix for now and then, if you have a lot of meseta, try building an endgame 4-slot piece of fodder. One suggestion would be:
Noble Might; Might 3 or Might 4; Alles Di Soul; Deus Factor; Arks MAX; Arks Fever
This would give you 135 or 140 Melee Attack (depending on Might 3 or 4), 12 PP, and 55 HP per unit (plus 65 ranged attack if you use bow on Anga). This is a pretty standard recommendation because Deus Factor is cheap at the moment (and often rolls with Escarde Soul which is useful for making Alles Di Soul) and there's another PSO Day next week so you can farm for Arks Fever if you're a Premium User (if not, hopefully the market prices will drop a bit that day). Might 3/4 can get pricey but there are also ways to make them from cheaper stuff or while upslotting. Unfortunately, Noble Might has been rising in price so you could always swap it for Might Boost (from the mission pass/player shop). Or you could swap in Noble Stamina at which point you'd probably switch Alles Di Soul (more HP) for Acto Di Soul (more melee). Fortunately, both souls require the same ingredients to make so you can decide at the end.
I use the Affixing Assitant to see possible ways of making the affixes I want and then play around in the affixing simulator to check variations on my final recipe. Here's one recipe on the simulator that would get you there:
However, that requires a 40% augmentation aid due to Deus Factor (which shows up at 90% in the link because you have to type in "10" in the text box next to "Campaign Boost" at the top of the page for boost week). So you could go back to the affix assistant to see if it's possible to raise the percentage on Deus Factor and you'd see that if you include 1 more copy on a piece of fodder you'd only need a 30% augmentation aid to reach 100% success. You'll also see from the assistant that you can swap out Vol Soul and Escarde Soul for other options if they're cheaper on the market, and there are many ways to arrive at Might 4 (e.g., Mutation 2 could be useful).
Here's the link to the affix assistant, which will also show you a viable final recipe, but I like the simulator for going back and forth between different recipes. https://malulleybovo.github.io/PSO2AffixingAssistant/