Hi Adam, I personally use the Wimberley Gimbal MK II (Current version) on a Gitzo GT3542LS Series 3 Systematic Tripod which is a Cracking piece of kit but comes with a expensive price tag. I use to use the Beike BK-45 just for static shots of wildlife as for inflight stuff I always use handheld as it is much better imho, but then again it depends on your physique if you want to or can handhold that lens all day which most won't. In Terms of mid range gimbal heads I personally have no experience in that area if i'm being honest with you, due to the simply fact I have gone from the basic to the top of the shop head so to speak, I have heard Benro GH series gets good reviews? But couldn't tell you much more from my own experiences to be fair with you.