I’ve been doing comparison batches, like you describe. It’s helped me to really learn what the yeasts themselves contribute. I prefer starting in a 6 or 7 gal, and by the time one is racking it gets down to 5-6 gal. I’ve done smaller batches, but really it’s nearly the same amount of work to make a batch, so it’s more time efficient to make a larger batch. I share with friends, so it goes fast enough. Tho’ the trick is to make more than you consume so there is plenty to age for longer periods. Most brews will develop a more complex and smoother flavor profile over time.