VX-1 12volt

Tapping a pack is never a good idea. It sure will get a pack out of whack fast. Use an isolated DC-DC converter like a computer power supply. A Brick! Cheap enough on eBay, maybe under twenty bucks or so.All computer bricks are DC-DC converters even though they say 100-250 Volt AC 50/60 Hz. Maybe you can put as low as 84 volt on a brick? But 100 volts is good. Efficiency is best at 192 volts, but even 350 volt DC will work too.
The first real discrete component is a Full wave rectifier. I have proved it myself with Lead based batteries and NiCads then again with race car battery packs. So little current but AH got totally mismatched and ruined. The old Cruising Equipment AH meter needed so little current I too tapped the pack and kept losing rather expensive T-145 batteries. Then Trojan of Worcester verified it for me. After a year all cells / batteries were dead on the monies equal within a few hundredths of a volt again. Keep series string series and not tapped.
How is VX-1 switch doing for you?
If you need a 12 volt brick then see if it is 12.0 or 15.0 volts and sometimes there are 13.5 volt bricks but 12.0 is the most common @ 6 amperes. Usually called monitor power supplies or now they are called LED adapters and usually come in 2.1 mm plug but others are widely available. Some devices need 12.0 volt exact but other accept 10-15 volt input. Same thing if you need 5.0 volt power source too. I use them all up to 28.8 volt bricks. Also they come in IEC type plugs and most common is IEC 13 but they can come in Mickey mouse and figure 8 variety. If there is a problem then you can just pull connector. Like instant off.
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the bikes dc-dc doesn't have much in the way of spare capacity - 1 or 2A at most

if you use too much, your tail lights die

there is no always on 12v (well there is, but it's just full pack voltage linear reg'd down to 12v, so not worth it)

if you need always on 12v, then hardwire a dc-dc

just pay attention to the continuous current draw