Gull Lake has decent perch, best bet is to punch a few holes drop down perch gear and see what is happening. Try all sorts of assortments. A wire worm and maggot works well.
Brownlows landing is a good place to start, but don't limit yourself there.. Gull is a decent size lake.. the schools will be moving and so should you if you want to increase your chances of finding anything of size.
Also it might be worth a shot to try Isle again... you never know until you give it a shot. Start at some of the ice shany towns in the north east part of the lake and work your way around some of the islands. The perch are in there, hard to locate but when you do you can get a few decent ones.
Other than that, it is hit and miss for them buggers... I have been after them for years, like many.
There really is no secret spot or honey hole... it's hit and miss most of the time.
Have fun hunting for them, I know in about another week or so when NAIT classes end for the semester I will be hitting the hard water trying to hunt them down. I find that the best time for perch is near the end of February..
Cheers!
