I still don't really see a point to not getting a decent bit of Def on Vella. Anyways there are actually quite a few setups that come to mind.
http://vindictusdb.com/item-comparer?i=blackhammer_head:blackhammer_upper:blackhammer_lower:legend_foot:legend_hand;whiteshark_head:whiteshark_upper:whiteshark_lower:legend_foot:legend_hand;glasgavelen_head:glasgavelen_upper:glasgavelen_lower:legend_foot:legend_hand;glasgavelen_head.0.3:glasgavelen_upper.0.3:glasgavelen_lower.0.3:legend_foot:legend_hand;blackhammer_head.0.3:blackhammer_upper.0.3:blackhammer_lower.0.3:legend_foot:legend_hand
5 Sets are...
1. Exquisite Black Hammer / Apocryphal
2. White Shark / Apocryphal
3. Raider's / Apocryphal
4. 3* Raider's / Apocryphal
5. 3* Exquisite Black Hammer / Apocryphal
Replace the Apocryphal Gloves/Boots with Swift pieces until you hit Lv. 70.
BH/Apo is the typical optimized set. Good Str, good Def, and it's full plate allowing for Tutelary Sentinel or Tutelary Resistant to get a bunch of extra Def. I'm at just under 10k Def with this set, and I didn't even fully optimize it. If you can afford it, getting 3* pieces isn't a bad idea as you get 100 or so extra Att, a bunch of extra Agi, and more Def.
Raider's/Apo is the more typical balanced offense set. Since Raider's is light, you can put Well-Balanced Force or Well-Balanced Enthusiastic onto it for 300-600 extra Att, at the cost of some Def. You can also get 3* to 4* Raider's piece if you have the extra funds. The issue here is that you give up quite a lot of Def for only a bit of attack.
White Shark/Apo is a Vella only combo, and it's actually quite good. It has two light pieces for WB/F/E and one plate piece on the part that most people throw generic enchants on (Enduring Master being most common). It's just flat out better than 2* Raider's, and it honestly could give 3* Raider's a good run given it's 600 Def for 10-20 Str trade off. The big drawback of WS is how expensive it is, the hat easily goes for 30m+. Also since it's a Titan drop, you can't get 3* versions of it.
Full Raider's is always an option if you want to go full WB/E/F, but I don't suggest it.
So in short, pick the one of those that sounds the most affordable to you, but also has the stats you want. The 2* combinations both cost around the same, the 3* and WS both also fall into the same price category. Feel free to pick up 3* Apocryphal gloves/boots as well, I only didn't include them as that'd be a consistent boost to all sets.
Just note the differences only come into play once you start throwing enchants onto them. Base equipment all looks close, until you realize (per piece) Plate gets an extra 300-600 Def and Light gets an extra 140-300 Att (and Speed/Bal/Crit) from enchants.
Addendum:
I didn't include 70 sets as they're too expensive and actually lose/break even to certain 60 combos on paper. So there's no point investing the extra money into a set that isn't significantly better. Apocryphal Gloves/Boots are only used as they're relatively cheap and give good stats.
80 gear is way too expensive, at like 600m-800m per piece. So I ignore the fact it even exists, since it'd be too easy and too pointless to say the best set is full pirate.
And don't try to bother with 4*. The price jump from 3* to 4* is huge, it's just not worth it.