If you could post some pics of it, especially the headbadge, I may be agle to help you out. Ross classifed thier frames in inches (19,21,23,& 25) so I'd say yours is a 25". I sold a complete bike with 19" frame about a year ago for $360, shipping included. The pedals were Campagnolo but not the original "Triomphe", the tires were not original, the handlebar wrap was NOS but other than that it was all original in good shape-about 7 out of 10.
I'm not sure what the frame alone is worth because what makes it valuable is the Campagnolo Triomphe parts. I've posted a pic of the Ross spec sheet for the 924S.