Which BB for White Industries Single Speed Cranks?

Thanks Ron for your insights, do you think that a 103mm Sugino BB would work with my configuration?

Regarding the chainring, I’m planning to use the 44T chainring that you refer to with a 18T cog and 170mm cranks. Since I’m not very familiar with optimal gear ratios I would very much welcome any advice or suggestions.

A 44 tooth chainring is more than enough. Track cogs go down to 13t and a 44 * 13 would be pushing it for anyone on the road at 88 gear inches.

On the the hand 44 * 18 is on the low side at 64 GI and is what I use on my off road bike and can get a bit spinny on the road if you are new to it.

An average gearing is around 70 GI, so either 17 for 68 or 16 for 72.