Hi Double Lunger,
Mind if I ask your fps with that set-up?
Speed is good, but it ain't everything.
I took most of those species with a Mission Riot IBO of 310fps. when I started. Range from 20-30m.
My setup was 29" dl at 70lb. (unfortunately I did not chrony at the time)
Easton Axis Carbon N-fused 30" with a 150 Slick trick BH. (still my favourite for African PG )
my arrow setup is around the 500-525gn mark & I got complete pass-through on all but the BWB with a q away & warthog I spined.
I've stepped up with a Matthews monster at 73lb now, it is "old" but dead in my hand. I will be taking on sable later this year with the same arrow set-up. 290 ish fps which is more than enough.
Note shot placement is everything. African PG vitals are a litter more forward in the chest cavity. It is seldom that you will get a perfect broad shot.
I found the majority of well used game paths tend to enter the clearing to the bait / waterhole directly opposite the hide, most animals will head in a semi straight line. be patient, after eating / drinking they tend to move around & linger a little, granting the better shot if they are not spooked, nervous or aware of you. I do a recce of the Area I tend to hunt a day before or so to give me an idea of activity to expect.
Suggest you study hard on shot placement & make sure you can hit the mark out to 35M. Most shots from a hide will be within that range anyway.
I prefer to aim for the high heart shot, destroy the arteries and damage lungs. Avoid full frontal or far quartering on the heavier boned animals. they are tough!
Warthog, Impala, duiker & steenbok are prone to string jump, hell I even had an alert blesbuck dip my shot.
Pay attention to the animal's behavior, don't risk a shot at a nervous animal or one that is aware / looking at you. wait for it to relax a little.
Two blade setups can be tricky to get right, make sure your bow set-up is 100% if you still battle to get good groupings, spin those arrows to see if the bh's are perfectly aligned. I normally weigh my BH's & batch them accordingly...same for the arrows.
Also pay attention to a good silencing package. Fortunately the Mathews bows are fairly quiet normally, the heavier arrow setup will also help but check your dropdown arrow rest for contact on the rizer.
It is about what I can think of now in terms of advice, but to answer your question, your arrow weight seems fine to me.