I'm trying to ship a bunch of small steel blocks used in a weight vest. I have about 30 blocks in total. They weigh about 2.8lbs each and are about the size of a bar of soap.

Question:

Is it cheaper to ship them say 10x at once. so 10 bars of soap (small box like 12 inches x 5 inches x 5 inches, heavily reinforced with extra cardboard and padding inside 28 lbs per box, and ship 3 boxes.

Or break them up into say 5 per box, and 6 shipments . each box about the same size maybe a tiny bit smaller (I'm cutting and glueing my own boxes and reinforcing heavily) with each box being now only 14 lbs.

Or maybe just ship 40lbs at once in a small-medium sized cube? twice?

How much does the overweight fee come into play vs splitting it into multiple shipments? And can the box be "too small" to put a label on at the UPS Store?

If it is in multiple smaller boxes, I would ship it over a few days one or 2 boxes per day. To give the UPS guy a break instead of 90lbs in one trip

What at your tips to do this?

Thanks