dual gauge idler cars

I find the dual gauge idler cars used between Alamosa and surrounding towns to be an interest that is not discussed much. I have a number of questions that include:
1. Why was 1 of them numbered with an X prefix (X3050) while the rest were numbered with a 0 prefix like a lot of the other non-revenue cars (010792 thru 010798).
2. Were there more cars of this type than these 8 used maybe used in Salida or Montrose and long since destroyed?
3. I would assume that crews hated dual gauge duty because of the number of movements (work) required to get past draws on wyes.
4. I know that one of these cars (010798) was used as a frame for the SLVS diesel, two were preserved (one at the Colorado RR Museum and one on the C&TS). What happened to the others? Scrap?
5. Did these cars ever cause trouble in switching such as because the force was not down the center line?
6. It appears that these cars were spotted on some track in Alamosa until needed and then carried to a destination in a freight movement where they were spotted for a freight in the opposite direction to use for local pickups as necessary. Correct?
Anyway, any information that you knowledeable guys would like to share will be appreciated. Thanks.