One need not be a certified splicer to do good work. Good instructions and training/practice are another story.
The question is not whether to buy a single spliced eye & eye prussic, it is how many and at what length I might need, and how often they will need to be replaced. I believe in self-sufficiency, and I would really be pissed to become dependent on a bee-line prussic, only to discover that I needed another one, and I had to wait two weeks for the next one to show up.
Right now, I think I understand the difficulty the professional splicers have in offering spicing instructions for this rope: This type of rope requires a class II double braid eye splice (I think), which is actually quite easy to do. Unfortunately, it requires six fid lengths of cover beyond the core insertion point to pull back enough cover to expose sufficient core to do the splice. When slicing the second eye splice, you run out of room to pull back the cover far enough to complete the second splice if you are working on a short section of rope.
There is an additional risk of disrupting the first splice by pulling back the cover while doing the second splice. Furthermore, I am concerned that details of the slices might make the prussic to stiff to use properly for a VT. Overall, it is a bit tricky to do well, and so far no one is giving me the instructions for the proper technique.
I have made one eye & eye prussic, but the cover ended up being too loose, it was about 1 foot too long, and it just wasn't good enough to climb on. Until someone gives me better instructions, I will just continue to experiment until I figure it out on my own. My first attempt will make a dandy chainsaw lanyard; it's just the right length for that.