I made a front weight for mine using square tubing and filling it with used lead tire weights. Can leave the weight on with either the fel on or off. (most tire shops will give you the weights)
Any chance you can post a picture of the weights that work well with your FEL? I've got a B7300, which is a small tractor, and with the loader on there isn't any room to mount weights up front. I'm always looking for ideas as my property is very hilly.