Excellent linky there Garbone . Thank you! Some good info .
Since this one will be a 2/3 leaner to start with I will be going for the zero-scrub. Was good to confirm that on your link. Combined with the chair being narrow/kinda short, with the seat center between the leading edge of the rear rims and the swing arm pivot points will provide about 1 square foot of optimal area for load (butt). Does make for a small area for CG so very minimal cargo will be able to stow in the nose. It's mainly a puppy/grand kid chair anyhow.
pic added of basic design though not to scale