Bach in March WEEK 1: Practice Updates

GerryM I love you guys' beautiful discussion as a passive watcher. Hope my entry will not interrupt that intellectual exchange. I listened to the András Schiff YT recording quoted by you.
I felt it's quite a long prelude contrasting to the fugue. The prelude has a meditative chorale in the middle of commotion-like parts and the following energetic fugue. That to some degree reminds me of the Eusebius and Florestan. Thus, I felt it's OK to play the fugue a little "mad" like both of you mentioned and would like to play the fugue as quick as I could. And that quicker tempo also made the left hand 3-4 (or 4-5, if mad enough) trills less painful (?) because that lessen the number of playable notes. I listened Mr. Schiff do the LH trills much shorter than the RH trills. Maybe it's really really... hard. 
I think there is a trade-off and also balance between the dilemma of the overall tempo and left hand trills simultaneously with contributing notes of another voice. To do the overall tempo quicker may helps the left hand acrobatics less trickier? 
For me, cadenza-like passage in Mm.8-9 of the prelude also drop hints to the ecstatic character of following fugue. 
Although I don't have the quick hands, it's still aluring to play the fugue quicker if considering the following the heart-breakingly beautiful dark E-flat minor - tragic prelude and forgiving fugue - which reminds me of Chopin op.10 no.6.
Again for me, all these contrasting and extremely emotional characters make the Book I more vivid, earthly and humane than Book II to which I owe a lot of listening and learning.
I apologize for my going to extremes.
Is it possible to do the left hand trill using 2-3 or 2-4? For the time being I don't have a piano beside me. 

Xiao Hi Xiao thank you for your comments! I agree I will try hard to have a contrast between the prelude and the fugue- they are of very different character. I will try to make the fugue lighter and more exuberant than the prelude. The possibility of shortening the trill (number of "shakes", as Hilda said) exists so as to increase the tempo- I've been trying that out. I like your references to Eusebius and Florestan- I imagine Schumann, if he were alive today, would be saying something similar! 

Hilda Huang Thank you, Hilda. I really appreciate your insightful opinions. I agree that different registers' characteristics make huge diversified effects, especially in modern pianos, and I also respect András Schiff's aesthetic choice of Bach playing. I remember that He always love seeing artworks in the Palace Museum when he visited Taiwan. IMO, he really appreciates the aesthetics of moderation. He kind of rarely go to the extremes yet he has the ability to do so (it's really hard to be prized in Tchaikovsky competition) and I had listened to some excerpts of his playing Brahms piano concerto no.2. which is greatly different from what the public knew about him.
However, what I in lesser degree agree is that many notes in lower register could caused muddy resonances. Your excellent playing of the A major fugue BWV 864 says that it can be clearly exuberant even if the bass passage runs in insane and also sane way. I always hope to have that kind of detach touch with my poor left hand (my index finger of left hand also have some problems) and that never came true. Dang Thai Son more than once mentioned about "detached touch" or " Le jeu perlé"  in his masterclasses. Also Bruce Liu apparently get the real essence of that in his wonderful rendering of Chopin op.2 and op.11 (especially the 3rd movement...) which I listened again today. 
I supposed that kind of touch really plays a big role in the E-flat major fugue, BWV 852 and repertoire including but not limited to Bach and Chopin. 

I learned about some practice methods which may be deemed old-fasioned from my teachers and some pianists. It helps a lot with my right hand, but cannot make my left hand learn from my right hand. Maybe I just don't pay attention to the left hand as I did with right hand. I had watched Dominic's video of left hand repertoire and gathered all the pieces in my e-ink reader but i wasn't really into it yet. I deem it's time to drill deep in improving left hand in this particular Bach month since there's no such second hand thing in polyphony. As long as I don't defeat myself in the first place.

Hilda Huang GerryM  Harriet Kaplan Anthony Miyake Brother Will Green  Thank you Hilda for the feedback, it is most valuable, and Hello to my fellow WTC Sojourners and correspondents. I would like to apologize for the sporadic nature of my postings. This is our busiest time at the office (I'm a tax lawyer by day [and night these days]) and it's making it difficult to make the time right now to post.  I'm inspired by your generous sharings of your thoughts and performances and I am trying to reciprocate by getting the Bm Prelude & Fugue from Bk II recorded for Bach month. I thought I knew it --  but ARGHH, mistakes are popping out everywhere! -- it's like that 3 Stooges episode where Curly is trying to fix a leak in the plumbing  -- with every attempted fix a new one starts shooting water out at him!  I'm slowing it down and hoping to get a marginally acceptable recording in before the month is up.  In the meantime know that I am checking in whenever I can and following all the postings with great interest!