Just used unetbootin on 7.1 B1 to add 7.1 B1.1 iso to usb and installed. no special requirements.
Easy, just like the VL install. My box does not offer boot from usb so I used the PLOP boot manager which boots what ever is available..find it here if required, works with floppy, cd, etc.http://www.plop.at/en/bootmanager/plpbt.bin.html
My guess is unetbootin on windows works the same.
usb shows under a gig used so 1gig stick would likely do
For a future project perhaps as Getrb does not have one free at the moment. I borrowed an empty one myself (lexar)