Well, your strategy of using the SmartCharger on a regular basis to exercise the battery and not let it sit at a full charge state all the times is viable, too. The only disadvantage with that is that you’ll be burning up charge cycles on it while you could have saved the charge cycles for only when you truly need it on the go.
If you’re going with the store-until-you-need approach on the SmartCharger, I would only charge it up for only 2 hours from depletion, knowing that a 4 hour charge would provide a full state of charge, so a 2 hour charge should give it roughly a half state of charge, the medium where the battery is the happiest.
If the charge state LED indicator does light up during charging to let you know what level of charge is in the SmartCharger while being charged, then another approach (instead of timing it for 2 hours like suggested above) is to keep an eye on it and keep charging until 1 LED shows, then 2 LED shows, but stop before or right after 3 LED shows. So 2 out of 3 LEDs showing would indicate a 66% charge, which is not the ideal 50%, but still better than 100%.
Sometimes charging Lithium-ion batteries is not a linear process time-wise, meaning that charging from 0 to 70 or 80% full may go more quickly, then charging the last 30 or 20% takes a lot longer. In this case, the “time the charging” method and stopping at 2 hours may not get you to exactly 50% state of charge, it may go beyond that a bit. So you may have to eyeball the LED state of charge indicator as described in the second method or use a combination of both methods for best result if you want to achieve 50% state of charge.
I know that this is really nit picky here because of my engineering background. In general, just avoid keeping the SmartCharger at full charge or at full depletion state continuously day-in day-out for weeks-on-end or months-on-end, and it will minimize the stress on its battery.