How to specify mana usage from my mana pool?

I'm playing a 4 color deck with 4 Lotus Cobra and 4 Evolving Wilds. It is not unusual for me to have 4-5 mana floating in my mana pool. Managing the mana colors is important, and the "auto pay" solution will not pick the colors of mana I want it to use out of the mana pool.

Is there a way for me to specify how mana is drained from my mana pool?

According to answers to this question on Reddit:

If you have a mana pool with specific colors that you want spent specific ways:

• Switch to full control mode by pressing Ctrl + Shift.
• Cast the spell by dragging it like normal. [Note: the spell won't actually be cast. See next step.]
• Mandatory color payments will be automatically pulled from the pool, but generic mana requirements can be paid one at a time by clicking on mana symbols.
• Once mana has been paid, spell will be cast.
• If you mis-click, you can hit Z to undo previous clicks.