just IMHO, I do not recommend 5.2B.
I feel 5.2A will give you the same safe 12x reading as original, and that using 5.2C or D will give you access to both speed. If you favour the 4x reading, I would rather recommend 5.2D. It has 4X as default until an original is inserted, giving you the options to run your backups at 12x as well.
I have seen a few people caught having problem with only 4x (5.2b) , and they had to reflash
also note that if you want to do 4x read speed, I would recommend using the best media (verb).