You will be fine, I've taken row 45 on an A359 and it is fine, I didn't notice there was a toilet 3 rows behind me
To distance yourself from the lavs on the A359 if you are still concerned, I would recommend sitting on the right side (G, H, J, K seats) because there is an extra row of economy on the right that will give you greater distance from the lavs, but it is fine either way.