:O had a read through the first article (all 13 pages...i feel i've learnt something) definately a lot of factors answers

also pretty much rules out Jet type block...too difficult to achieve good results ...heck..i don't EVEN have a pump or ANYTHING yet..
need to try and find out what's better...Rotor/slit saw random channels with water pumped through middle ******ds with a slit for water to go through to increase velocity ...or just 2 connections. One at either side with slit saw straight microchannels ...hmm..