Hi geologist,
I have only once used a monopod, my actual walking stick, and missed a very close shot at a warthog! Looking back, I believe I had the rifle slightly off to the right hand side, and the shot went astray. I would have done better just shooting offhand, and possibly about 5 seconds earlier!
Tripods work much better for me (only used twice). More stable, but practice with them (setting up and actual shooting) before going out. They are heavier, and more cumbersome, than a monopod, but worth the effort. My one son (6" 3") has a very long bipod on his 30-06 Mauser 98, and he can shoot it sitting, and does well with it. I find it too heavy, and would prefer just sitting with elbows over/in front of knees. This obviously depends on having short grass/shrub.
With the 3 species mentioned (impala, warthog and bushpig) you will usually get quite close, and distance will most likely be under 75yards. You may also have a tree for support in daytime hunting (mostly impala and warthog). Your guide / PH or his tracker will then have to carry the shooting sticks.
Most outfitters/reserves will have a tripod/set of shooting sticks, so no need to take one. You can make one very cheaply (for practice here) by buying 3 extendable handles for painting from the Dollar store. Mine are bright red, but cost less than $10 for all 3, tax included. These have "nylon/plastic" tips, so may slip on concrete floors (my indoor range) but work well on natural surfaces. I also use these for setting up my Chrony.
My last four hunts were about 180kn south of Johannesburg, and my shots varied from about 60m (impala) to red hartebeest (80 - 140m) and blesbok out to 220 m. However, my oldest son shot his blesbok at about 80m, and his wife (about 140m sitting, resting over my shoulder), both on walk and stalk, both using 308 Win with handloads. Shots in the open plains will be much longer, out to 300m), and these will be blesbok and blue wildebeest. If you are willing to walk, you may get an opportunity to get much closer, and shooting sticks may not be needed.
RSA1