A few thoughts:

First a Motobecane almost certainly has Swiss threads are you using the threadless VO BB?

Any VO BB will have a JIS tapered spindle, what crankset are you using? Wether Japanese or French your bicycles stock crank was likely intended for an ISO tapered axle. What this means is that your chainline is likely further outboard than stock as is.

My recommendation is to set it up the way you want it and experiment. The combination of a modern chain and friction shifting should be very accommodating.

Also your use of the gears can be a big factor. For example if only you only seldom use the low gears than having the front rings further out may not be a very big deal, or if you seldom ever use the 2 or 3 highest rear cogs than having your front chainrings inboard a little may result in a better chainline in the gear combinations you frequently ride in.

https://www.sheldonbrown.com/bbtaper.html