Azzlevt,
You will not locate an easy button for this one. Trial and error, talking to other fisherman on your local lakes and reading local fishing reports will help. Your local DNR or fisheries management division may be of great help too.
The questions you ask can vary by weeks or months dependent upon location. You may be able to scan the IS Forums for specifics to your State/area.
You have already noticed as posted prior, that as of last weekend, the Perch were spread from 4' to 30 FOW in different locals. Good Luck locating those Perch!
Get a Vex, and begin your own research. You may discover your own honey holes for this time of the year, tha no one else knows about!