be aware to check his perfusion frequently when yu have him bound,, nawa shibari is perfect for long term rope bondage and has several sites devoted to it as fetishdj mentioned above
its my owners prefered method of binding me,, we use jute and or hemp a lot(need the friction no knots in traditional shibari), and nylon climber's rope, as well as a softer more plyable type of rope i dont know the name of that he gets from home depot for other types of ties.

also be aware pressure points over the bones can rapidly develope into "pressure sores" which are just like a bed sore in the hospital in many ways, i recccomend slow going at first, leather cuffs with some rope, short durations , at least till yu are more comfortable