Hello.
This is a building-related question, but none of the existing forums fit the profile. Since pergolas are all timber, I am posting it here.
This is my first attempt at building a pergola. I saw many designs
online. It is almost finished, but I have a few specific questions that I couldn't
answer. Please, have a look at a photo below.

(for some reason can't have it shown here - either in dropbox or onedrive) I attached the picture to email...
1) Do I need a couple more battens on top?
2) Currently, the rafters are not screwed to the beams. There is at least 3.5" of
wood before a screw will go to the beam. I thought maybe there is another way to attach them. And, since the whole battens+rafters structure is rather heavy, do I have to attach the rafters at all? With the added wines it will be even heavier...
3) If I put 8' x 4' plexiglass sheets on top of the cross-members to make a roof against rain, would the grape wines be able to grow up from the sides and duck under the plexiglass? I presume that they could grow under, if I will be manually guiding them. There will just 2" of space between plexiglass sheets and the tops of the rafters.
Thank you.