Piero and Pat! I had some extra time to spend practicing during this lesson.
Regarding the damping in bars 9-11 in rondocino, I found that for bars 9 and 11 adding 'i' to the mix was just unnecessarily complicating things, as the only reason to do so was not having to damp 'A' with thumb, but that damping pretty much comes for free by using (a light) thumb rest stroke for the 3rd quaver 'E'. Therefore I didn't use 'i' for bass notes in those bars.
Bar 10 is a different matter, and there I found that I have two options: Either use just thumb, which practically means that the 2nd quaver 'A' needs to be played staccato (or left ringing, which doesn't sound good). Or use 'i' to play the 3rd quaver 'D' allowing the 'A' to sustain longer before damped with thumb. The problem is, that having initially learned using the first way, unless I'm really concentrating, I still tend to play the 'A' short, and sometimes forget to play 'D' with 'i'. So to answer your question, for bar 10 I find both ways equally difficult (or easy), the difference being how long can I sustain the 2nd quaver 'A'. I also don't see much difference in damping the 3rd quaver with thumb regardless of which finger was used to play it. The trick is to use the same movement we practiced in the first lesson (I think) with those simultaneous playing and damping (with different fingers) exercise. It's basically like playing a block chord with all four fingers, i.e. plant all the fingers at the same time, but just don't play the thumb.
Regarding bar 17 of the intro, I find using i-p-i both difficult and not very satisfying tone-wise. In the recording those thumb strokes aren't very accurately timed. I think I usually make a better job with that, but cannot really be sure. There is a similar study among Giuliani's 120, and I find that very difficult as well. The index finger needs to be so much flexed that producing a good tone with it becomes very difficult. Another thing is that playing the wound strings with i/m/a roughens the nails worsening the tone, and I find that I need to buff them more often, so I tend to avoid unnecessarily playing the bass strings with those 'melody' fingers if it can be easily avoided. I still do scale practice with them normally, and use them for bass strings when i-m alternation is needed. Isn't p-i alternation supposed to be quite old school anyway?
For me the process of playing for video seems to be of unpredictable nature. Sometimes it goes easier than expected, and I end up doing 3 takes that get progressively better, and just post the last one. Other times (as was the case with Sonata) my playing gets progressively worse, and I begin to experience all the symptoms of stage fright. Sonata was especially difficult because on Sunday I had filed down my nails, and as that cold sweat got into my fingers, the nails just seemed to disappear inside the fingers. Mental note to self: when having to perform, allow one or two days of nail growth before the performance. What was required for sonata recording to succeed was a single sip of wine to calm the nerves.
In my opinion, even if you keep the camera on all the time during the practice, things just change when you know you are recording for real. At that moment, for me at least, it stops to be about stopping to polish any section you happen to have problems with, and starts being about getting it first time right. For the first time with that specific piece of music, there starts to exist a possibility of failure. As long as you're just practicing, you cannot fail. I guess that's really the key, and also explains why recording the same piece for the second time is so much easier. Failing to improve upon a previous success isn't nearly as bad as failing altogether.