I find that a mass fab makes uu matter a bit too easily.
for that i want to suggest a new machine. sort of a large accelerator. no more magic block.
it's a circular construction similar to a large hadron collider in Geneva
parts are. coils, tubes, injector and collider chamber
the injector can use scrap to increase its production of 'protomatter' that is essentially the currency used to create UU.
coils: need to be powered with sufficient EU in order to accelerate the protomatter. more power means more speed means greater production in the collission chamber. they also are needed in the corners to redirect the stream.
tubes: to shield the stream and transfer it to the next coil.
construction. it's always a circle like pattern you need to follow. the matter must make a loop.
coils are always needed in the bends in the circle , but can also be set in between. tubes in set between the coils.
Coils improve the production according to the power they get.
tubes increase the production by a small set amount .
simplest construction would be 6 blocks: the injector, the collider and 4 coils for the bends but with very low yield.
the bigger the circle the greater the production speed can be made by means of the number of coils used.
recipes are based on alloys and advanced circuits.