I don't have a 1440LB but these style gearhead lathes are all similar. Oil weight will matter if you live in extreme climates & don't have a climate controlled shop. Bakersfield is pretty much similar to LA. Here's what I use in my PM1236.
Headstock & apron: ISO68, specifically Mobil DTE26. Any ISO68 hydraulic oil will be fine though. Some people use Vactra #2 way oil in the apron & Grizzly actually recommends the same on some of their lathes.
Oil ports (except the power feed rod & bed leadscrew ends): Mobil Vactra #2. You should really use way oil here. #2 way oil is equivelent to ISO68 in weight. If ISO32 is all you have for now, that's better than no oil at all.
Oil ports for the power feed rod & bed leadscrew ends: Mobil Velocite #10 spindle oil. This is equivelent to ISO22 in weight. I used to use Vactra #2 in these ports in the past.
But if you lived in areas that are extremely cold like freezing temps, ISO32 would be a better choice for the headstock & apron. If you live in extremely hot areas (like hot Socal days in the summer but mostly year round), ISO100 might be a better choice for just the headstock.