The cycle analyst gives you a lot of info, volts,amps drawn, ah[amp hrs] used, max volts, amps etc. It uses a shunt that you connect between battery and motor/controller with only a small gauge wire which goes to display on h'bars, if your not much at soldering you can use connectors such as anderson power poles. But require a special crimper to do the job properly. From what I have read on here ,Other types of meters such as 'watts up' use heavy wire to display and return to controller.
I have a CA fitted on my elation, its ok if you want to know all the above info but in my opinion the leds on the THROTTLE are all you need, the yellow led will illuminate at about 22.5 v, if you don't change down gears or pedal harder the red led will come on, followed by lvc [ low voltage cut off], so use the gears and pedalling to keep green led on as much as possible, naturely this will become more difficult as the battery reaches the end of its charge
You say instructions state use 20 to 30% throttle, I think it says 80% or 80% of max revs which is 2080 rpm [ max 2600] ebikes are at their most efficient at about 80% of max revs, too bad someone can't come up with a rev counter for ebikes.
BTW most ebike throttles are a little touchy, something like all at the end are all half way around.
One way is to raise rear wheel off ground run wot [wide open throttle] then back throttle off slightly to try to judge 80% revs, listen to motor sound then try to keep it the same when riding , using throttle , gears and pedalling, eg, I use middle crank and 5th gear with moderate pedalling to ascend 5% grade.
Imho, powering from a standing start is a waste of batt charge, pedal to about 10kph then slowly add power, remember these are a pedal assist not a motorbike.
Ninety percent of riding will be with front gears middle chain ring, the large one for high speed on flat or downhill, small one if you want to climb up the side of your house.
Always release throttle momentarily when gear changing, especially front derailler.
200w elation v3