Single Combat

How do you folks indicate your choices when in Single Combat?  If both sides spend blindly it implies doing *something* to lock down the decision so that the second person to vocalize their choice can not change to adjust to the first speakers choices.

We wrote on index cards last session. 

It was suggested everyone have a deck of cards next time and we could correspond suits to choices, so if (for example) you took two hearts and a club from your deck (looking through as you choose, not blindly drawing) you chose to deal +2 harm and take +1 armor.

I'm bringing a dollar tree bag of those vase-filling glass beads to the session this week, and I'll have them secretly place a bead on (or under) the 'harm' 'armor' or 'experience' section on their playbook for harm, armor, or positioning bonuses.   We'll see how that works.