TLDR: My setup is to use the GT2 Tomahawk with my monopod, the GKjr Katana Pro (std mount) with my tripod and my MH-100 probably needs to go on the auction block.
I have the
Wimberley MH-100, the
PMG GT2 Tomahawk and the
PMG GKjr Katana Pro gimbal head (std tripod mount, not side mount). I was even able to purchase both of the PMG gimbals when they were on sale, so keep an eye out for those opportunities.
I used to use the MH-100 on a monopod with my Nikon Z9/500 PF combination and it worked ok. It's small and functions adequately, but I was still interested in looking for other options that might provide more stability. So I got the GT2 Tomahawk to replace the MH-100 and I couldn't be happier with this product. The GT2 Tomawawk is sturdier and a
much more stable platform to shoot from with a monopod then the MH-100, and it's a joy to use. Needless to say, I haven't picked up the MH-100 since I got the Tomahawk.
I've only had my 600 F4 TC for a couple of weeks now, and I have used it with both the Tomahawk on a monopod, and the GKjr Katana Pro on my tripod. Both of these gimbal heads work well with a big heavy lens like the 600 F4.
There is no way I would choose to use the MH-100 with my 600 F4, even though the weight of the lens + camera combo would be within the weight tolerances for the MH-100. The Tomahawk and the GKjr are simply much more robust options, with more functionality as well.
I decided not to go for the GKjr in the sidemount configuration, mostly because I prefer the naturalness of operating the camera with the lens oriented over the top of it's lens foot and centered on the tripod. Some people say there might be more stress on the lens/tripod collar over time when you use the side mount, but I doubt there is any evidence to indicate this is actually true. That's probably the most common mount configuration when using a monopod, and I haven't heard of any issues with this setup.
You could go with the "two birds with one stone" setup of a having a side mount gimbal head that works with both a monopod and a tripod, but for myself, I went with the gimbal head solution that I preferred for each support system individually. Yes, it's more costly this way, but I get the gimbal head that I want, where I want it.