As suggested in #21, why not toss out 2C and rearrange A +B +D on the top row? This should allow you to expand the figures which would make the legends more readable. Or, you can keep A + B + D in their current arrangement, and then use the extra space in the corner to put a legend with larger fonts.
Fig. 4. Figure 5: Normalisation approaches made easy with scater.
Presumably, and to avoid confusion with scaling normalization:
Fig. 4. Normalization and batch correction with scater.
As suggested in #21, why not toss out 2C and rearrange A +B +D on the top row? This should allow you to expand the figures which would make the legends more readable. Or, you can keep A + B + D in their current arrangement, and then use the extra space in the corner to put a legend with larger fonts.
Presumably, and to avoid confusion with scaling normalization: