Just a clarification:

HQ-HZ front floors are all the same, from firewall joint through to the integrall crossmember that runs through the front seat rear bolt holes. WB are different, the seat hole nuts in the floor closest to the tunnel are in a different place.
The best way to change the floor is also a BIG job, involves unpicking hundreds of spot welds off the donor floor.

I'd also just use the sedan doors.