Had both 70-200 f/4 IS and Canon 100mm USM macro. With a ~50mm extension tube, it's not so good as a macro lens because the minimal AF is so long still.
A longer telephoto macro will work but you will likely need a tripod or hand-holding with flash. DOF is just way to shallow at smaller aperture.
150mm's MFD is not that much more than 100mm though. It's still only 15in for 150mm vs 12in for 100mm. At 1.4x TC, 1:1 MFD willl be somewhere around 18in.