we use an automated comment to prevent it from going to waste

You can do this by following a curation trail. Check hive.vote and how curation trails work. Let's say u follow a trail at 99% vp, so it will only trigger after mana is at 99%.

We power them up to continue growing our influence

Doesn't matter. What if blocktrades does same everyday when his mana is at 99%? He can also use the excuse that he is not cashing out.

we’d love to hear your thoughts

Just go to hive.vote
Follow any curation trail and do settings that it only follows autovote when vp is above x %.

This solves your issue of using extra vp. My problem is u earning both author and curator rewards which is self voting. If everyone does the same, the system will collapse. And if one person can do then others can use an excuse that why can't they do it too.