Are you sure you want to split your patella twice for a little more than an inch? Externals are annoying and have to be worn for a long time but otherwise you might end up with permanent knee pain for the rest of your life. In case of just 2,5cm's you will probably wear them for not longer than 4 months. You'd also be wheight bearing from the start.
Not to talk about the financial aspect of externals compared to precise.
I'm only considering internals because a certain doctor said, due to a (non-LL) slight deformity I have, I might be able to get insurance coverage. But I agree with you...I think I'd rather do externals and be weight-bearing. Tibias scare me regardless, but that last inch I want would make my femurs way, way too long (they look just fine now, even if slightly long).
If I could get my last inch and be out of the frames in 4 months max, then I might be able to pull it off and not completely ruin my career/job. It's all based on that. And I'd go to Dr. Catagni most likely (or see if Rozbruch can do externals, I don't think he does them anymore).