I do have an observation/comment on this layout...
some of these components are VERY tight together - like the 22nF cap between the two trimmers, the 1n beside trimmer 3, and the 4n7 below trimmer 4, and all of the 1u caps.
so they fit just fine. i know that if you'll be using the squared once i't going to be a no way.
let me know if you want me to change the layout so that you can use bigger trims
*no i haven't tried this yet. i have tons of other things to do...