Baume & Mercier - AS/5008 - Left wound spring

[sstakoff]

Stripping down my B&M Capeland (I will be posting many photos to the walkthrough forum when done). One little surprise - one of the the barrels (there are 2) has a left wound spring. Of course, my Bergeon winders only have right winders (plus a #15 left that I purchased for a pocket watch). I plan on ordering a left winding arbor next week. Beside hand winding - which I really don't want to do - anyone have any other techniques? I though about using a right winder,  and inserting it into an old aluminum mainspring retention ring (like those that new springs are shipped in), flipping that upside down and pushing it it - like you would for a factory new spring.

I need to hit the supply house regardless since the bridle on this particular spring broke