Couple things about ice fishing Sebago:
If you don't have a flasher, you're wasting your time.
You can set traps if you want, but you'll catch more jigging with a flasher.
If you're marking fish and they aren't biting, switch lures, lighten your leaders, etc. Keep switching it up until you find a combo that works.
Just because they bit really well in one spot one day doesn't mean they'll bite well there the next.
Matt and I fished a completely different portion of the lake on Sunday vs Saturday. We literally got home, had dinner and opened up the chart and found a drop off that looked good, one that I have trolled in the past. Matt had a fish on in the first two minutes of fishing, in the first hole that we drilled just to check the depth.
When it comes to numbers of togue in Sebago, there are tons. I will say that making them bite is tough. I've never gotten above 10% of the fish i've marked to bite, and it would be an absolute slaughter if I could get 50%.
In the summer, if a person knows what they're doing and is honest to goodness targeting togue, they can catch them one right after another at any hour of the day, most days. Most people who troll Sebago are only interested in Salmon, maybe that's part of the problem?
The number of fish in Sebago are not the problem. I blame their unwillingness to bite on two things:
1. Sebago's extremely clear water makes it so you can't get away with using heavy leaders, or poor presentations.
2. The abundance of bait makes it so the fish can eat whenever they want and thus aren't starving to death, ready to slam anything that moves, all the time.
It's a challenging lake to fish, but that only makes your success more rewarding.