I'm going to bounce around in my reply here.
To start, your final comment that your time is limited on the ice. I know exactly what you mean when you said that. As a person who makes a large portion of their income preparing tax returns (during ice fishing season), my time on the ice is also restricted. But I used the reverse logic as the reason to spend my money on one of these things. With so few days to be on the ice, I wanted to maximize my chances when I could get out.
Now, with regards to flashers. They do have a slight learning curve if you have never used one. A flasher unit will do somethings an LCD can't, and an LCD does other things better. The biggest issue when on the ice deals with "the picture" being updated faster, while not having to deal with the historical picture that scrolls across the screen of an LCD.
The concept of a flasher's picture is that you are looking at a series of brief images set on something that looks like the dial of a clock. The surface is always set at "Noon". As an example, if your flasher is set for 20' and you are currently over 10' of water, you will see a broad band sitting in the 6 o'clock position. 15' of water would put you at 9 o'clock, and so on. If your unit is set to shallow, say in 30', you won't get the bottom echo at all, and you will need to set the flasher to a deeper setting. With the deeper setting (say 40'), now the 10' reading would come in at 1/4 of the dial, or 3 o'clock. You always want to set the flasher at the minimum depth you can get away with. It allows you to see the most detail.
Now let's go back to that 20' setting, and set up in that 10' of water. Your dial shows a bottom echo that isn't going to move or change. You may even see a second echo further down the dial that you can disregard for now as it is only a secondary echo. What you watch for are the brief flashes that show up between Noon and 6.
When I first get on the ice, I set my gain button on my unit to the day's conditions. To do this, I will drop my teardrop w/waxworm on it dow towards bottom. You will be able to watch the echo from this slowly move down the dial. Then I adjust the gain until my bait shows up as a small orange echo with a touch of green on either side. Now, if the waxworm is missing, the signal will change to only a green band. This adjustment can be done with a variety of baits such as perch minnows, or larger baits for walleyes, lake trout, or pike.
A brief item on signals. Just like any other fishfinder, the signal is sent out in a cone shape. On a Vexilar, the flasher reads the strength of each signal and shows them in color based on that strength. So, a fish near the outside of the cone shows up as the weakest signal (green) while targets closer show up as either orange, or red (strongest). Note that your gain setting will also have an effect on these readings.
Once you have the gain set on the unit, you're ready to do the catching part. Like I said before hand, I usually start my day on the ice by drilling a series of holes. These either spread down a drop line from shallow to deep, or broadly across a flat. Once all the hole are drilled, the gain is set, its time to start looking for fish. I do this by moving from hole to hole, looking for solid echos somewhere between Noon and where ever bottom shows up. Sometimes you'll see bright red echos (those are fish) and can immediately drop down your line. Other times, you may see just a brief glimmer of green. If you wait at the hole, the signal may strengthen as the fish moves deeper into the cone's signal under the hole.
A typical days will have me cover a number of holes. Once I find a hole with fish, I will stay put to see if I can get them to bite. As fish typically move around a bit, some holes can dry up. When this happens, I just repeat my search of the holes looking for one with a school moving under it.
Back to that double echo off bottom. With time, you can read that echo to tell what type of bottom you are fishing over based on the echo. It's kind of like seeing a bottom echo for the first time on a color LCD -vs- the B&W's version called "grey-scale".
Yeah, all of this takes a little time to learn, and I got most of my education by trial and error. To see some of this (and much more) you can go to Vexilar's website. They have a bunch of videos that show off their features.
Disclaimer: Just in case anyone was wondering, no I don't work @ Vexilar. They are not a client. I'm not even married to the owner's daughter. I've just become a very big fan of their product.