Is there a max number of virtual machines that can be backed up at a time using 
vadp from the vcenter side of the house?

We have multiple sites with multiple vm's at each site and this is growing 
rapidly.  I have a couple of physical vadp proxy servers at each of my sites 
backing these up, but with the number of vm's that are being added I need to 
backup with a more aggressive schedule.  Meaning, if I'm backing up 10 vms at a 
time in each of my groups, now I need to increase it to 15 or even 20 at a 
time.  I understand group and server parallelism and can adjust those numbers 
accordingly, but I'm wondering if there is a limit of how many can be done at a 
time from through vcenter.

My proxy servers are pretty big boxes with more than enough space (they were 
once my vcb proxies so they have a 2tb drive setup for just vm data, even 
though I know I don't need that much now)

Thanks in advance