As far as these open designs go, there's not a lot of difference between them as long as the layout is somewhat reasonable. All these have 40 tiles of active pipe in contact with the liquid. Gold pipe in with ceramics. Crude temps only: H 361 M 364 N 336 O 352 P 354 Q 357 The only real outlier is N. They get better the taller they are (Except H and M should be reversed; beats me.) The reason for taller=better probably the liquid being super goopy