PREC Form Customization

We have a critical requirement from a customer to increase the width of the PREC form (use the blank space in the left) and display more then 15 columns to show other critical information. I understand the current limit is 11.

This is a one-off requirement and customer is fully aware of the trade-offs involved in such such customization w.r.t handling the future version upgrades and associated maintenance issues. Customer is willing to go for it in few select screens.

Has anyone done something like this? Any guidelines?