The time I usually hit the Res for Perch is usually late June-mid July. Just the the Weed beds are beginning to emerge. Slip bobbers with small Leeches were the ticket and Perch were averaging 9"-12". Largest I seen a few years back was a 13-14" that someone caught earlier in the day and kepted it in a Ice Cream pail. It was a nice Humpty
Take a walk down on the Sailboat docks on the East side of the Res. In about 1-6ft of water, you should see schools the small Perch roaming around.
If you got a Canoe or a Tinney with Oars, you can do some recon and find some of the places that the Jumbo's are hanging out at.
Unfortunately these waters are not only governed by Provincial Regulations but also by City Of Calgary By-Laws..... (No motors, No Ice fishing, etc)