This article by Steph Davis explains the difference between twin ropes and half ropes.
We did experiment with half ropes using them to lead climb in the gym. Some real advantages if you are traversing or if you want to avoid the possible longer fall you get when clipping high above you when using only a single rope. (It’s easy to understand when you try it; it’s harder to explain in words.) I can see an advantage if there are only two climbers doing a multi-pitch where you need to bring two ropes in order to rappel. Since you can use half ropes as twin ropes, I think getting half ropes would give you more flexibility.
“Half ropes may be clipped separately or they can be clipped together so that both strands are clipped through every protection point—this is called twin rope technique. Dedicated twin ropes are lighter in weight and bulk, but should always be clipped so that both strands pass through every protection point.”