Bouts = "leftover" randomly-shaped trapezoids/rhomboids/etc. that remain after first extracting as many rectangles as possible.  For the record, they obviously had bouts available to them miners to try and sell a century and a half ago, too...I guess back then they assumed there'd be plenty of rocks forever.

Bouts are great for establishing bevels, and present no limitations at all for water-only finishing to me.   Depending upon their shape, they can be limiting for going from bevel-making to the final finish via continually watered down slurry, and thus you can see the rationale behind why my primary preference is for stones with ultra-high water-only speed.   With enough square footage (particularly in any one long axis), bouts are absolutely fine and of no meaningful difference.   Bouts are always the best value per unit of area, too.

Bouts are cool; I'm privileged enough to say I was once briefly an Aspen, Colorado ski bum (94-95, ask me about mid-Feb. when we had ~100" in 10 days followed up by 26" after the lifts closed and before they opened, people were hurling themselves off the Steeplechase edge just to land in bottomless chicken feathers), and bouts remind me of skiing Aspen Highlands instead of Aspen Mountain.   While the latter's more famous, nearly every run falls straight to earth...most runs on "Highlands", however, simultaneously fall down and to a side.  In this opinion, one learns more of skiing in that complex realm, and one will better learn honing's essence on a bout than on a rectangle.  Honing's primarily about what you're feeling with any one part of the edge at any one time on any one part of the stone.   Become accomplished living that philosophy and you can hone upon circles.  To loosely quote the brilliant 1980 masterpiece Caddyshack, "be the edge" :-)

• # 3 Bouts = 22-27 sq. cm a perfectly-average "perfect" parallelogram would be 1.9 x 1.9" (49x49mm)
• # 4 Bouts = 27-33 sq. cm a perfectly-average "perfect" parallelogram would be 2.16 x 2.16" (55x55mm)
• # 5 Bouts = 33-39 sq. cm, a perfectly-average "perfect" parallelogram would be 2.4 x 2.4" (60x60mm)
• # 6 Bouts = 39-48 sq. cm, a perfectly-average "perfect" parallelogram would be 2.6 x 2.6" (66x66mm)
• # 7 Bouts = 48-58 sq. cm a perfectly-average "perfect" parallelogram would be 2.9 x 2.9" (73x73mm)
• # 8 Bouts = 58-70 sq. cm a perfectly-average "perfect" parallelogram would be 3.15 x 3.15" (80x80mm)
• # 9 Bouts = 70-84 sq. cm, a perfectly-average "perfect" parallelogram would be 3.45 x 3.45" (88x88mm)
• # 10 Bouts = 84-102 sq. cm, a perfectly-average "perfect" parallelogram would be 3.8 x 3.8" (97x97mm)

What lies below is amongst what we're best known for as a shaving shop.

The most challenging bout (polygon) shape to me is an isoceles triangle, and the easiest a parallelogram.  With plain water use for touch-up/finishing work, to me any shape's of no limitation.