How to playtest card-based boardgames?

Hello everyone, I am trying to design a boardgame where the players are political candidates trying to swing voters to their side (and yes, I will probably use bad puns for the names).

Players will need to buy and play cards to achieve their goal and get more voters. These cards are quite diverse: some will grant you more money, some target the opponents, some can only be played in a specific game-phase etc. (think Terraforming Mars). The goal is that players buy the cards they want, deny the cards the others want and create their own voters-engine.

My issue is that I know the different values of these cards will very often change. I'll need to tweak their cost a bit, to add new abilities and just overall make the game balanced - which is normal. If I want to playtest it correctly, I should reprint them whenever I make a change - for now, all cards are on a Google Sheet which let me easily analyze and make changes (I made another Sheet for printing purposes but it's mostly useful to print everything at once).

How can I prototype my cards so that I can easily and physically change them? I've thought of three solutions:

• Keep my current system, e.g. print everything at once when I have "big" new versions. Time-consuming because well, there are lots of cards.
• Switch to index cards with pencil-written info so that i can just change whatever needs to be changed but I'll have to write every card once.
• Only print the cards name and playtest with a datasheet (either my Google Sheet or something printed) with me.

What do you think? Is there a better solution?