Time Capsule, iTunes and disk images?

[Shrewdude]

Since I cannot partition the Time capsule's HD, I was planning to create a disk image and put my entire iTune library on this disk image (as suggested in a previous thread). This will avoid Time Machine to chew up the entire disk space. I currently run my iTunes from a main folder on the TC without any problems or conflicts with Time Machine.

1) Will it be a problem if different users try to access the iTunes library from the disk image at the same time?

2) Will running iTunes off a disk image on the TC 'slow down' iTunes, in particular videos?

Thanks!