Believe me,all trollers have problems figuring out if fish are on the line or not,regardless of the technique you are using to troll with.I love using inline boards and they can really help you get out more lines and cover more water.There is a learning curve with all aspects of fishing and trolling is no different.The more time you spend on water trolling and reading forums like this the better you will become.Another great way to speed up that learning is going with or having someone with more experience join you.
We have changed the configuration of our boards over the years to what we run now.We have the tattle flag that goes down when you have a fish on.We use rubberbands(size 33 @ OfficeMax) on our boards.Like them better than the springs that come with board.You can adjust tension on the flag by moving the rubberband over the leading edge of the board.Easy and quick to adjust.We use the Black OR18 release on the front arm and the red OR16 with pin in it on back release.We are using Maxima 15lb mono line.Some people use braid,but the braid can slip through the releases much easier than the mono.The boards are much easier to read in calm water.You can tell if a fish on by either the flag going down or if running multiple boards,by the position of the boards in relation to each other.You have more problems if the waves are bigger and a lure and/or weight that is pulling hard.The flag will only go down if there is slack line between the two releases.The problem,is the line pulling through the releases with that extra tension,till all slack is gone and the flag won't go down.I normally wrap my line once around the back OR16 release to prevent it slipping there and tighten the OR18 release so you don't get slippage there either.
Another thing to do is when you initially putting boards out and not sure of rubber band tension on the flag,you can put your lure out and when you get the line positioned on both releases,hold the board with your hand and see if flag goes down or has too much tension on it.Move the rubber band over that leading edge to fine tune tension then put board out a short distance and lock the reel and see if flag doing what you want before putting board into proper position.
I think seeing that flag pull down and the board moving back is the coolest sight indicating a fish is on.Better than all the other big board or dipsey aspects of trolling.