adding a switch to my rear view camera

I'm going to add a switch to my rear view camera so I can check on whatever I may be pulling at times, I'm just going to put a 12v switch on the camera power lead, but I need to know what size diode to put on the other end of it so my reverse lights won't come on, and send voltage through the reverse light wire when I flip the switch. I know a 12v diode, but what amperage do I need?

1n4001 or any number between there and 1n4007

Hope you don't mind if I tag on to this as I'm doing the same. When adding the diode, do you have any suggestions on how to add it in? I looked them up on RadioShack and didn't see any that are inline like a fuse holder. Should I just solder it in and cover with heat shrink?   Also can you tell me which side the stripe should be on? I believe the stripe goes away from the reverse light source and towards the camera/ACC switched source. Also, why only a diode on the reverse light source? Wouldn't you have the same power feedback issue if the ACC source is switched on and you throw it into reverse? Therefore needing two diodes setup in opposite configs stopping power going back to each source? Thanks for the help. This is all new to me.

I found this video that was helpful on attaching a diode in line in a wire. http://www.eaavideo.org/video.aspx?v=713336874001