Granted, these times may be either longer or shorter than the average time for each stage, but this should give some idea of what times to set for each stage.
Green Grove Zone:
Act 1 - 0:27
Act 2 - 0:55
Act 3 - 0:47
Rusty Ruin Zone:
Act 1 - 1:27
Act 2 - 1:55
Act 3 - 0:53
Spring Stadium Zone:
Act 1 - 1:08
Act 2 - 1:36
Act 3 - 1:21
Diamond Dust Zone:
Act 1 - 1:26
Act 2 - 1:20
Act 3 - 1:18
Volcano Valley Zone:
Act 1 - 1:25
Act 2 - 1:09
Act 3 - 0:30
Gene Gadget Zone:
Act 1 - 1:13
Act 2 - 0:36
Act 3 - 1:26
Panic Puppet Zone:
Act 1 - 1:08
Act 2 - 1:25
Act 3 - 2:02
The Final Fight:
Act X - 3:59