[Volenti]

I have successfully removed the perspex block from the cpu (it was epoxied on) On close inspection all that could be seen on the core was very faint...marks... that are in a pattern that would match the contact points of the jets in the block, however as I rubbed the core some more with a peice of clean cloth to see them more clearly they slowly faded away, interesting.

I have also found a suitable, re-useable and safely non-permenent sealant to use in future direct die cooling, with that in hand I replaced the multiple jets in the block with a single 3/8'' intake(as an expriment)

As expected the flow rate shot up (I havn't measured it, though at least triple the flow of the multiple jets) and also (mostly expected) the block performed worse;

mulit jet, (temps in degrees above water temp)
idle 10
load 10.5

single 3/8''
idle 12
load 15

interesting to see the jet impingment theory in practice...