intresting numbers, do you have any pics of your rig?
...thread officially hijacked ;p
on topic.
my 2 cents would be go for the 12H if you can get one for good money.
I love my motor, the grunt in these things when offroading is amazing, had a 3L hilux on 38" before and always had to be playing with the gears to keep going, the 12H just keeps on chugging even at 1000rpms in 3rd (high drive), well, if that´s what you are looking for

on the down side the damn throttle can be a pain in the

.
I haven´t driven a 1HZ myself so I really can´t comment on that motor and the 1HD is just so f-ing expensive I don´t see that it´s worth it over the 12H.