Futtock Shrouds and Staves

I have a couple of questions regarding the futtock shrouds below. I realise that these were probably not preserved with the Vasa but there should be some indication from other ships of the day.

1. What was the shape of the futtock staves? Were they round rods, or did they have a rectangular or square cross-section across the shrouds? I guess they were made of timber and not metal (eg iron).

2. I assume the staves are mounted below the tops about the same distance below as the head and cap extends above the top. Correct?

3. There doesn’t seem any point in having ratlines across the shrouds behind the futtock shrouds, that is, between the futtock stave and the top attached to the main shrouds. Is this correct?

Any help appreciated.

Thanks,

PeterG