Hi Steve,
I follow the book and don't use fixed minimums, but it is easy to add a constraint for a fixed minimum transaction value.
Lichello replaced the fixed minimum buy/sell of $100 with the 5% minimum transaction(3rd edition).
Page 265, 3rd edition:
'Make your minimum purchase or sale 5 percent of your Stock Value....'
Page 54, 3rd edition describes the $100 rule.
Kind Regards, K