yes the chain and jug is the spacer, and by using a chain one Can easily adjust the length to what one wants or to adjust to the eye of the helper to get the spacing,
the travel speed is less than one mph, it takes some time to get the next tree out and to position it,
ones hand normally does not get near the press wheels, on the front there is a shank with an opener on it, and then there are the two sheet metal Shields that hold the hole open and is about 16" long that way the roots can be properly placed in the slot in the earth, and then moves the tree at ground speed until exiting the shields until the ground had moved back around the roots, supporting the tree, and on the normal your hand is well removed before the tree is near the press tires,
unless your moving slow the person on the planter will be over whelmed in trying to keep up. moving at one mph, you have about 15 seconds to place a tree, and if the tree has any problems in removal out of the box, or bucket or if bare root and tangles, if I remember correctly about 3/4 mph is what works about right for most people, (many tree planters are two seat so there is two planters working in alternating planting),
on the shrubs that were 6 foot spacing you really get a work out,
I normally provide the rider, with a loud whistle to blow if any problem occurred so the driver would stop instantly to allow the problem to be corrected, the whistle was just good so there was not a hearing problem,
