I have been eyeing one on Amazon. The poundage will be fine. It's the pad you put him on. It's going to be to small later on.
I use a wide plastic jar on the scale and zero it out.
That way, he is evenly balanced in the middle and he can’t walk off or move around. Works well! Here’s an old picture. (Ignore the third leg) this makes things much easier and quicker weighing all of the torts... Kind of like setting a box on a can of green Beens