The pattern I am currently working on is a bit of a mess, but it does turn out beautiful in the end so I do want to repeat it...
The pattern is a hat, or well, they call it a baret. It is knitted, but has an edge with 4 rows crocheted, this is the part that really goes around the head and needs to be fitted. The "lose" part of the baret is knitted, and when done it has a (round) edge of about 70 cm.
I tried this pattern before and managed to make it 54cm in the end, by crochetting very tight around the edge. However, it was pure luck that it turned out OK as I had no idea how to measure such a thing...
I did notice that the first row I crocheted reduced the size to 56 cm and the second row dimished this by another 2 cm while the next two rows didn't change a thing anymore... Not sure why (but it was very lucky

)
So I wonder: is there a more organized way to go about this? Like knitting a gauche and crochetting the edges to see how much stitches one would need for a diminishment of 16cm ?!? Or rather a "measure as you go" way ?!? Or a way in which you split up the hat-edge in parts and diminish per part or something?
I hope I made myself clear

If somebody thinks it will be easier to understand my problem by reading the pattern his/herself I can post it - but I'll have to translate it first (that would be a small effort though

).