Digital BW, The Print

I'm interested in the three channel ebony inks mentioned on Paul Roark's 
website and have a couple of questions.

If I load the r1800 with the factory supplied inks(I haven't received
my r1800 yet) and want to switch to the three channel ebonies can I
run the flush cartridges and save the epson cart. for later. Are the
flush cart. good for only one shot? 
Is it bad to keep switching back and forth if its even possible in the
first place?

Thanks.
John