QIC to VXA-2 Tape

Have a customer who will probably shortly be moving from a 270 to an 810. 
They will be changing from 25GB QIC tape to 80GB VXA-2.  So one concern is 
obviously tape converion during the migration.  I see these possibilities:

1) Find a system with the capability to handlt both 25GB QIC & VXA-2 and 
DUPTAP.

2) Order the 810 with a 5702 PCI-X Tape Controller (or rent/borrow one) 
and attach a rented or borrowed  7207-330 external 30GB QIC.

3) After saving the 270 to tape, remove the 4586 25GB QIC drive from the 
270, remove the 4585 VXA-2 drive from the 810, install the 4586, restore 
the backup from the 270, then switch the tape drives back.

The last one is the one I have questions about.  I'm 99.99% sure this 
should work fine - the System Builder does list the 25GB 4586 as one of 
the internal tape drives attachable to the 810 .  The CD, DVD & Internal 
tapes are all the same size and in the past I've removed a CD drive from a 
model 400 to install a 2nd internal QIC drive and that went OK.  Does 
anyone know for sure that #3 above would work?

...Neil