Hi Wannabe, The wife and I take our vacation at Siltcoos every year in mid September. For 14 days straight it goes like this: Up at 5:00 am on the water at 6:00, fish for bass 'till 10:00 or so, come in for a bite to eat, on the water again for perch 'till 3:00 pm or so, come in, fillet the perch, have a beer or three, eat diner, go to bed, get up and start all over again.
The perch fishing can be phenomenal at Siltcoos from mid Sep. through Oct. I think most all of the costal lakes hold perch, we just prefer Siltcoos because of the amenities there. The last couple of years it seems like the size of the perch has increased with fish to 11" being fairly common. Last year I got one 14" and several 12". The last couple of years it has been harder to find them though, but when you do it's sure fun. We usualy bring home enough fillets, baged and frozen, to have a perch fry at least once a month, 'till the next years trip.
We've never fished for them in the winter so I can't help you there. Location at Siltcoos starts near the weed lines, or in sparse weeds, then as it gets toward the later part of Sep. the perch will move out to the mud flats in the deepest parts of the lake, 15-22'. My prefered bait is a strip of perch, skin on, cut from a small perch, the wifes is a piece of night crawler.
Hope this helps, It's got me missing the place just typing about it.