hi frayli,
we cut our own block and have got also got a private firm called davnic to do the retaining walls - our fall was 6 metres over entire block and we have some pretty big retaining walls around 40 metres (26 square metres) all wood, look great imo and for an extra 250 he would get them engineered (we didn't need this as they were under a metre - well just) - all up was $6000 which I highly recoomend them - did a great job and were very quick! we are now going with PD and site cost with fill etc were approx $14000 so we are happy but we are building the Marina which is big.
Lisa