Hi Chris,
Regarding my mod to get weight to the end of the plank for lighter cartridges, see the last picture on my virtual system page. I'll try to describe here. Go to your local auto tire store and get some stick-on wheel weights used on magnesium or aluminum wheels. Take the base weight off of the ET weight clamp. A portion of the wheel weight can be fashioned to exactly fit in the groove in the ET weight clamp. Once this is done it is simply trial and error to trim the remaining portion of the wheel weight to the correct weight for your plank and cartridge.
The stick-on weights come in a single bar that is perforated so one, two or three can be broken off according to how much weight you need. I started with two and shaped one to fit the groove, then trimmed what remained to get the correct weight. Hope this is intelligible.
PS: Lead weights are easier to work with but harder to find here in the lower colonies since the government has decided that just touching lead will make us all brain damaged.
Cheers,
Harry