Ah, sorry I missed that one. Tiger salamanders eat like they are starving most of the time. I feed mine daily until I feel like they've had enough, lol. Usually 3-5 roaches or a couple of large night crawlers. Females will eat more than males, and often look more blimp shaped. If you notice your tiger getting obese (rolls under the chin, on the legs, etc) just cut back on feeding. Perhaps smaller portion sizes or feed every other day instead.
If you fed a tiger as much as it would eat in 15 minutes it would probably explode, they are like bottomless pits. Every once in a while I will let my tigers pig out and eat as much as they will eat before going back to their hide. My female's record is 12 full sized lobster roaches in one sitting.
Size won't matter much. As long as the feeder isn't bigger than your tiger's mouth there will be no issue. My tigers have eaten adult dubia roaches that are nearly larger than their head with no complications, but I wouldn't reccommend doing that regularly.
My male eastern tiger hides pretty much all day and most of the night sometimes. When I walk into my animal room I go by and tap on each of the tiger's tanks. Whichever ones come out get fed. Any that stay burrowed will go without food that day. I kinda just let them decide when they want to come out for food. Sometimes they get fed twice a day, sometimes they go 3 days without food. Just kinda depends on their mood and mine.