[R-390] R390-A Gear Lubrication Oil Smell

[Larry H]

Before I cleaned and lubed the R390-A I'm working on, I read through the Pearls and forum for advice.  The overwhelming consensus was to use Mobil 1 75W-90 (or similar non-sulphur) oil for the gears.  That I did and it certainly works great!
However, after a day back in the house, I noticed a smell like a machine shop (mostly in my work room).  I thought since I put it on very sparingly, I would not experience that.  I guess I should have expected it, but maybe it's due to our air and heat not running this week.  So now it's back in the garage sitting.
Any how,  is there a good oil to use that has a lot less aroma?  I was looking online, and saw an oil for compound hunting bows that looks good and is synthetic and odorless - 'Spot On Lubricant - VersaOil'. It's viscosity is 50 at 40*C, which might be a little low.  The viscosity of Mobil 1 75W-90 is 103 at 40*C.  The viscosity of Mobil 1 10W-30 is 63 at 40*C.  The viscosity of Mobil 1 75W-140 is 170 at 40*C.  
So, is 50 to low of a viscosity to use?
Any suggestions that will let me bring it back in the house where I need it would be most appreciated.
Regards, Larry