circut board is not really stronger than polycarbonate, but it is half the thickness and that will give a you an extra foot of depth out of the same length lip. You can thin the front of a lexan lip to ultra thin but that is a lot of sanding with 800 grit sand paper.
The only draw back with circut board is a lot of hard cranking in rocks, it will slowly chip. I've got some baits I been banging rocks with for over 3yrs and and lips are chipped a little but nothing that hinders the action.