Casio Collectors

Hey Graham do you have any advice for swapping the DIP's? 

I'm ready to start but I'm not sure if I should solder wires to the old intact DIP pins to got to my ZIF sockets or if I should just cut out the old IC's and solder to just the left-over pin nubs.

If I leave the old DIP's in place do you know if I only need to cut the VCC and CE pins to the old DIP's or should I just cut all the pins and be done with it?

This will be for both the ROM and RAM chips.

If I was a glutton for punishment I'd remove the bottom board and desolder the old chips but forget that.

Thanks,

Kev