I have the BH-40 on a Gitzo GT2540F, which in my view is the right head size for that tripod. On a Gitzo GT1551T I use a BH-30. I believe that would balance the GT1542T better, even though a BH-40 also fits. A BH-30 is more than capable of holding the weight you´re looking for and it is less weight (not by much though). Both heads are working very well and I recommend them both.