OK, thanks! The Steem-Plus extension does provide an indicator for how much SP you have left, which is a convenient feature.
With my vote giving so little already, I don't know if it is worth having a slider though. I like being able to give and am eager to be able to give even more, so giving less seems counter-productive. With each vote my SP goes down, so I can stretch my votes farther by allowing my VP to go low, but I prefer to keep my VP over 80% in order to give the most I can. Often I will wait for my VP to recover before casting votes and sometimes need to go back a day or more to cast votes on things I didn't have enough VP for at the time.
I had to wait 5 days to recover 100% VP, my upvote bot (installed in chromium) made more than 60 votes, i barely saw 20 or 15 of them reflected in my account :-(
My VP was at that moment in 4.10. Lesson nr 1 from that: dont upvote with low VP, stop at 90% and wait to regenerate to 100%
I don't see a problem going down to 80%. From there it recovers fully in 24 hours. Mind you, I often am back at the computer and of course Steemit after only 8 to 9 hours, so in that time I'm not back to 100% but closer to 90%. That's when I start counting my votes!
Im going to try that, good tip, thanks.