I've been doing these massacre stacks for a long time. Wing stacking has been a thing for at least a year, just wasn't well known and overshadowed by mining.
I base my own operations in 13 Lambda Crateris / Xerebaye.
- 13 Lambda Crateris has 3 systems nearby: Bhaguthians, Hedete, Xerebaye to collect missions from.
- Xerebaye shares those systems, collect from: Bhaguthians, Hedete, 13 Lambda Crateris.
- These places have a lot of federal factions.
- Both 13 Lam and Xerebaye have 2 haz res around the same planet. I've parked my FC 'Endurance' in 13 Lambda Crateris around the haz. It's always about .1ls away from either haz, or closer.
- Main F star in 13 Lam makes the rings really bright. Nice spot to hunt in.
- There are no other systems nearby in the 10ly range. All pirate massacres generated will be for either 13 Lam or Xerebaye.
- It is not a powerplay area, so you don't have any annoying powerplay police in the rings.
A second spot to look at is Tjindjin and the Tjindjin Gold Hand Gang.
- Can collect missions from LTT 4961, LTT 5013, Weleserme, Catarihas
- Tjindjin 6 has a haz res and also an outpost, Ing Settlement, about .15ls away from the haz (iirc, it's really close), which has all 3 Rs available for medium ships.
- The mission pool can be somewhat diluted by anarchists from other places. Stacking here can take some more time.
- Edmund Mahon space. There will unfortunately be 'Alliance Enforcers' in the rings a lot, even in the Haz.
In the same area, you can also try stacking for LTT 4961, which has two (!) stations in the same ring as the local haz res. One of these stations, Greg's Legacy, is a neat asteroid base.
Albardhas is another good spot, but I've not been myself.
Quikuruba is also okay but I haven't spent a lot of time there.
- Lots of Empire factions.
- Non-powerplay spot, no powerplay police.