Nice job.
Somnatash -- she seems to be on top of everything about the Brompton -- can correct me if I am wrong, but the S-model has a longer and further forward stem. Judging from the picture below there is room for a wider and taller bar with the S-model. So if you are looking for a longer reach, you can do so with a bar with less rise.
Question: Most MTB bars I see are angled towards the rider. But using such a bar with a Brompton widens the fold. What bar did you use and did it widen the fold?