Recommend clean/dry silica sand instead of steel/lead shot.
It's commonly used for sand blasting.
However the dust from silica sand is not good for you, so fill them outside while wearing a decent mask and eye protection (not a problem once the stands are sealed up).
The 3 different stands I've owned/own did not require a "complete" fill (think my current Target HR's are only @ a third/fill after many trials including lead shot/sand with lead shot and sand only).
Big thanks to my Honda mechanic (may he rest in peace) for properly recycling the lead shot I no longer needed.
This said, the cheap stands I owned leaked the sand over time and now I only have the Target stands (20 years old and Zero leakage - wish I could claim the same @ 67;-)
No rec on current inexpensive stands available as I have not tried them, but look for top fill and secure enclosures/fill cavities.
DeKay