HIT training has been around since the 70's. i wouldn't say specifically that is what dorian yeates did, he did his own thing, with a lot of HIT principles. many traditional HIT workout stress body part with one exercise and do more of the body per day. dorian did more of a traditional Chest/bi, legs, shld/tri, back/traps type of routines each trained once a week. and not just barbell for chest but machines, etc... so a chest workout could be bench, hammer machine, db fly, machine fly instead of just a HIT bench exercise.
i think before going on to HIT you should try AST sports MAX-OT to get the principles in your head and learn what intensity truly is.
then on to how dorian trained or a variation of HIT or even DC training
for example you said "first day was leg curl, leg extensions, leg press, bench press, shrug, barbell bicep curl, then alternate chin ups and dips"
--> not a very good split in my opinion. any program advocating chest and legs on the same day regardless of training technique would be thrown out so fast. if i did 1 set of leg press to 100% intensity no way my chest is going to get a good workout that day