Update: Since Hench's reveal earlier today iGear have updated their facebook page with the following regarding the height of their next two Mini Warriors (the other being MW-04 UFO):
About the MW-03 Hench and MW-04 UFO, we plan to make them about 12CM≈4.7 inches, slightly higher than the other two released MiniWarriors, and the height of the rest Miniwarriors unreleased will be different too, depend on their scales in the G1 cartoon, will between 8CM to 12CM(3.1 to 4.7inches). We also welcome the proposal of the height of them, thanks.