Fitting a voltmeter into the horn wire

So after having a few charging issues with my daytona 955i i've decided i want to fit a voltmeter so i can see when riding if it stops charging or starts overcharging.

I'm aware that fitting a voltmeter that far into the wiring isn't going to give me the exact voltage but it'll let me know if anything changes while riding.

So what i was planning on doing was cutting the wire before it gets to the switch "so in theory it'll always have the same voltage as the rest of the system" and wiring the voltmeter in there, then attaching to the clocks. This way it would also be off when the bike isn't on as to not drain the battery.

The main questions are, would this work, and am i missing something stupid that i havn't considered?

Thanks