The bases are 1/8” thick with a 1/2mm magnet sheet adhered to the bottom.
The spear men could be cut, but only I think at two discrete points in the line. You can see them below – the hollows in the casting. That would give you a four-man, five-man and one extra from each strip. Would probably suit most purposes.
An alternative with an in-universe justification is to use the leftovers from Swordsman strips and give each line of spearmen a pair of swordsmen at each end to protect their flanks. I’m considering this as a possible alternative to slicing up spearmen but it’s more frugality on my part, not wanting to waste the little extra swordsmen. I’ll dry fit and see how it looks.