These are excerpts from several articles by Xilk, for those of you who don't know him this guy is the epitomy of the consumate Bst in my opinion ! [others like Kaoz & Abeo got me started on Bst in the 1st place]
He more than any other Bst I know has pushed the boundaries & has encouraged me with his actions to attempt things I would not have otherwise tried.
Here for those who like me are new to brewing are some interesting & useful tips.

Brewing Gear

I used atma of the beyond, ultimate and baying moon.
Hell's Guardian, Ultimate and beyond are probably the best atma for bst brew kills on bukhis, but I don't have PW kill.

The thing is, CHR and DEX really don't matter when you are brewing. They will be capped already.

This means you want MAB and Killer Effects.

I found /sam w/ Warding Circle was more effective than /rdm (I had more MAB than killer effects, so KE will be relatively more effective)
I grabbed some demon killer food as well… I don't remember which. Popping an Ascetics Tonic/Drink/Gambir would be great also.

I was doing 35k/rend. bukhis has 120k hp. I lost several wings due to skipping lotting between some kills. The first time I tried for 5x kills… brew ran out after 2 rends on 5th bukhis. Unless you can get Hell's Guardian & hit 40k+ /rend… If you go on Light day and use the atma from Indrik, you might get up there. Pretty sure you can break 60k and 2-shot him if you have all the bst stuff. you would need to lock the brew after each 3 kills to let the spawn points respawn.

I finished it mostly because I hate having my inventory w/ over a dozen alfard's fangs and having the farsha 1/2 finished on bukhis… (and I couldnt' stand to throw them away) but really I don't use it. I have 99 DA Ganelon & 99 STR Astolfo which both trounce 90 Farsha for damage (Ruinator FTW).

I might pull it out for amber farming… if I'm not using my blu for amber farming… and cuz cloudsplitter looks cool.
Primevial brew does absolutely nothing for pets.
Dual wield does nothing for brew.
The whole Idea of brewing a tough NM down is to kill alot of them as quickly as possible. You have like 100/tick regain going, so Weaponskills are your absolutely best bet.

None of the stats (str, dex, int, agi, etc…) matter at all for brew, because primeval brew will take them all to 999.

Because of atma and how brew works, Magical Weaponskills have a higher potential than Physical Weaponskills.
The max potential for the best physical Weaponskills under brew is around 10k damage.

The highest potential for magical Weaponskills under brew is around 65k damage (Wildfire, corsair, and bst can get this high in perfect situations also).

The way the magical and elemental damage boosts work, you pick your atma for exactly 1 weaponskill and spam it as quickly as you have tp.

Since brew maxes stats, your main ways of boosting damage from gear are to focus on Killer Effects and MAB. Nothing else will make a big difference.

Cloudpslitter can do more damage than Primal Rend if you have it from WoE weapon. Otherwise, w/ a magical ws it really wont' matter what weapon you use. for a physical ws, you would want the highest damage weapon you can get.