I'd like to see how that is done. 7.6.1 would fly on a G3. According to this thread
http://68kmla.org/forums/viewtopic.php?t=993
You can't even use a retail 8.0 disc with a beige G3. You must use the version that it shipped with or a later one so I don't see how you could in any way get 7.6.1 to work.