[Darren27]

Get someone else to do it.

Neoprene seals can be fitted to cordura type suits. Norther diver do (or did) fit neoprene seals to their early vortex suit as an option.  What ever make of suit you have Norther Diver do a good repair service.

As to the argument with neoprene seals leaking, all I can offer is this.  My suit has made to measure seals and has never leaked.  My wife is the same.  Of other members of our club who have neoprene seals, those with made to measure seals never seem to coment on leaks, those with off the peg suits complain about the seals.  

Make of that what you will.

Darren