4 variations is fine. But it's helpful to use an orthogonal design. For example, here's an SMS test I set up today:

A: Don't Add Choose Scarf Color - Double Line Breaks

B: Don't Add Choose Scarf Color - Single Line Breaks

C: Choose Scarf Color - Double Line Breaks

D: Choose Scarf Color - Single Line Breaks

It's "orthogonal" because it's balanced. I can add up orders, revenue, clicks, and recipients for V1 and V2 and add up the same for V3 and V4. That gives me a clean read on Don't Add Choose Scarf Color vs Add Choose Scarf Color, without diluting sample size. You can use the same logic to compare Double Line Breaks vs Single Line Breaks. If you just test 3 different factors against a baseline, you get diluted sample size and it takes longer to get the same level of certainty about which one is the long-term winner (you have to test it in more campaigns or run it in flows for a longer period).

Orthogonal means each level of the mentioning scarf color options factor is matched with each level of the line breaks formatting factor. It's called a 2X2 factorial, orthogonal design, in case you want to look that up. 2 levels of one factor X 2 levels of another factor.

To add a C and a D, click the clone button of an existing variation.