Hi Blackjack,
My personal, and not necessarily correct, feeling is that you might want to think about a rear dirt scoop instead. You can load them with sandbags, etc., and you also have an implement which can serve multiple purposes.. such as moving dirt, etc.
What I ultimately did was get surprised when a neighbor built me a great rear weight from a 55-gallon drum. I'm wrestling a bit with the easiest way to connect it. I have it set up now with a solid top link, but a pal at work in cutting me down a normal top link and welding it up for me.
I don't have a FEL.. instead a front blade.. used mostly for plowing snow, pushing out rocks, etc. For snow plowing, I used to put 600-1000 lbs of sand bags in the rear dirt scoop, and we guesstimate the drum weights about 1200 lb.
Don't know if any of this helps, but probably it can't hurt. /forums/images/graemlins/crazy.gif