Custom Variables in event tracking with multiple values in 1 slot

I sort of have several questions,

1. Is it okay to have custom variables in an event tracking (_trackEvent)?

2. Can i have multiple custom variables in on like like

   pageTracker._setCustomVar(1, "language", language, 3);

   pageTracker._setCustomVar(2, "category", category, 3);

   pageTracker._se开发者_如何学CtCustomVar(2, "subcategory", subcategory, 3);

   pageTracker._setCustomVar(2, "topic", topic, 3);

   pageTracker._setCustomVar(3, "video-id", videoId, 3);

   pageTracker._setCustomVar(4, "duration", player.getDuration(), 3);

   pageTracker._setCustomVar(4, "buffer-left", player.getBufferLeft(), 3);

3. And if i could have multiple values in a slot, can i have find a report like how many video with duration more then 2m is played (the event) under subcategory a of category a

4. I dont quite understand the 64 bytes limitation, is it per track (all of the custom variable) or per custom variable (key-pair value)

Thanks in advance

1. Yes, you can do that. Now whether or not you should do that depends on your KPIs and business needs.

2. No, you cannot do that. There are a total of 5 unique custom variable "slots" (1-5). You can set one or all per hit, but you cannot set the same one more than once in a single hit; you will just overwrite the previous value. If you absolutely have to do it, you must break it up into several hits (multiple _trackPageview or _trackEvent calls).

3. You can have multiple values in a slot, but you can't set multiple values for the same slot at the same time, see #2.

4. The char limit is for the full key-pair value