Amount of Rapid Start for very small batch?

Hi-

I got a sample of Rapid Start from the local store, and I was really impressed with the results. Unfortunately, I knocked the bottle over. I only have a half tsp left.

2 questions: 1.) Does RS last awhile after being mixed with water? If so Ill just mix the rest and use it for the next week.

2.) Does anyone mix very small batches (water bottle sized or smaller) by counting drops or something similar?

I'm hoping I can stretch the Rapid Start long enough to water 3 seedlings for another week when I'll be able to get more.

http://generalhydroponics.com/site/gh/docs/prod_labels/RapidStart.pdf

The application rate is a ratio. So no, you don't have to mix 5 gallons at a time. you just need to keep it in proportion.
1/4 mL per liter. You probably have enough to make up a couple of liters. There are about 5 mL in a teaspoon.

It's worth just going out and buying the big bottle, very good stuff.