What piece of glassware would enable the measurement and transfer of these solutions with the best combination of speed and accuracy?

The pipet would be the best tool for mixing speed and accuracy. Pipets tend to be used on volumes that are in the single-digits of milliliters, so they can be used to measure out tiny amounts of solutions. In addition, they can be measured to dispense volumes almost to-the-drop, so not only they can be very accurate, they can do so quickly.