How do we manage individual developer resources per sprint?

[My Kro]

Ok with Greenhopper 6.2.2.2 I can see my backlog, throw issues into a sprint, no problem. But I'm trying to get my head around how the system can help us manage multiple projects (X, Y), multiple developers (A,B) and their availability. Say we've decided that each developer can do 8 days of work per sprint period. 1. How might the system prevent me from allocating 12 days of work to Developer A? 2. I allocate Developer A to 5 days on Sprint X-1 and 3 days on Sprint Y-1, and Developer B to 6 days on Sprint Y-1. How can I have the system alert or inform me that Developer B has 2 days unallocated? I suspect the answer is to use some sort of Report or Gadget that maps all sprint issues onto a timeline separated by assignee but I'm having a hard time figuring out whether I can get this information in the default install or whether I need a plugin. Thanks in advance for any assistance!

[Timothy]

I don't think that there are any add ons at the moment that does this but you can take a look around. One thing that I can think of is creating a filter that filters a specific sprint ID. With that, you can use add ons out there that do sum of numeric fields to find out the number.