SOPP721: Since I have some problems with my eyesight and was looking for a somewhat large written edition of Bach organ music

Let’s start episode 721 of Secrets of Organ Playing Podcast. This question was sent by Massimiliano and he writes:
Hello Vidas,
How are you?
Since I have some problems with my eyesight and was looking for a somewhat large written edition. I wanted to ask you please what editions you use for Bach's music. In your videos I can't understand it well. 
I also wanted to ask you if you know a good manual for organ improvisation in style or if you can recommend something for study.
Massimiliano