A laid back seat post would not be practicle on a highwheeler,to get the bike to pedal in a straight line pedal pressure is applied on the down stroke of each pedal,if you are sitting too far back you would be applying pressure on the forward stroke of each pedal ,result you would be wobbleing all over both lanes of traffic even with a death grip on the handlebars,if you ever saw anyone ride a highwheeler they just seem to glide along,it just takes a little practice to get used to the proper pedaling procedure,once you do you can ride with no hand pressure on the handlebars. Also be very carefull using the brake,apply it gingerly while leaning back slightly to shift your center of gravity ,lean back when riding over even the smallest of bumps in the road ,never ride off of a curb(instant header) and practice the emergency dismount (jumping off the back of the bike while moving,grabbing the backbone of the bike to save it too),there are videos on youtube of the emergency dismount.