Yeah, 1.5 Greg is changing how thorium and plutonium work, so what works/is most most efficient will likely change. Whatever the changes, if a multi-fuel type reactor is ends up the best again then you will still need slot level inventory management.
The critical part to managing these reactors is putting the correct fuel in the correct slot. Each reactor has 3 types of fuel and each type needs to go into one or more specific slots. There are some slot specific inventory tools available, but GT advanced regulator seemed to do it in the least space. It only has 9 storage slots, so supplying the fuel in the right ratio is the next challenge.
I posted a setup of the breeder + 3 production reactors in this thread:
http://forum.feed-the-beast.com/thr...to-power-matter-fabricator.16327/#post-186188
Save is also in that thread.
To provide a specific inventory level I used railcraft. RP2 managers could also do the job, but RP2 does not use ghost items. Golems don't handle multiple non stackables well. AE emitters are slow to change, so you get more of a range near your target level rather than your target level.
For slot specific inventory management some alternatives to advanced regulator (9 slot):
turtle + inventory upgrade (any number of slots)
router (1 slot)
advanced buffer (1 slot)
If you are going big into nuclear then a router setup might work well. You would need 8-9 routers per type of reactor, so the more of that type you run the bigger the benefit.
Turtles always work. You could even use an AE export bus next to the turtle for each type of fuel and let the turtle pulse a certain bus when it needs a type of fuel.