IMO the reason why a thicker base plate is better is so it can spread the heat out sideways before it gets to the water, hence more surface contact with the water.
Making yours wider IMO will not improve performance because with a BP that thin the only place getting hot is right above the core, maybe it would improve performance by letting more water flow though.
With the
blocks I have made, mainly rotor style drilled ones, the differnce between 2mm and 3mm base was about 10C!
BTW i like your design
all these people making there own is great
