Grazyna, thanks for your post.

Your questions are good ones. Here are a few suggestions.

1. Replace the 1-5 scale with a simple yes or no, e.g., Are you satisfied with the knowledge transfer process?
2. Instead of asking them to quantify the value, which is hard to do, ask for one or two expected benefits.
3. Ask no more than 3 questions of any one person.

By keeping the number of questions to a minimum and not making anyone have to think too hard about a 1-5 rating or a quantitative value, you can assure people that it will be fast and easy.