L1, L2 Visa

Hi,

My company filed L1B blanket petition last year and it got rejected last December. Last month, my attorney again filed for L1B individual in premium processing. Few days back I have got RFE which is massive. I have figured out most of the answers and evidences. But need some help in below questions :
-How to prove specialised skills. - I got multiple training and my on job experience which helped me to gain most of the critical knowledge. I was fortunate to work on various issues and projects which gained me thorough knowledge . I dont have any certificate for the trainings I got. What should I do and prove that I have all proprietary skills?
-How much to write while answering every question. I got more than 10 questions specific to my skills. Does answering within 5-10 lines is good enough Or it has to be very detailed and long answer.
-Should I be very specific to the technology I am working on (which means, office might not understand most of the things , since its proprietary technology) or should I be very generic so that office can understand (but then I dont want him to think, its not specialised knowledge)
-For few questions, I am planning to take the printout of mails and internal slack chat (where I got appreciation) and send it to officers. Is that acceptable as a proof ?

Also how do I answer questions which says, what benefits organisation got because of your knowledge Or skills ?
- I am in engineering team. So dont have do any selling or marketing . And my name doesn't come in any of the published document. How do I prove what impact or benefits my org has gained from my work?

Any help here would be greatly appreciated. Thank you in advance.