My 1930 B has Houdaille shocks (round ‘can’) so I can’t comment on Delco Lovejoys.
Gear oil (I also use these products in my two Series 80s and in my 1922 Paige 4-pass. touring):
For the differential, the most important thing is to use GL-4 (hypoid) oil rather than the more readily available GL-5 (suitable for limited slip) or GL-6 (synthetic), as both GL-5 and GL-6 contain sulfur which will attack bronze components, especially bushings. NAPA stores sell Sta-Lube brand in both GL-4 and GL-5 in quarts and gallons. As to weight, since we’re both in California I recommend SAE 140 if you have not had the diff rebuilt. For climates that drop below freezing more than very occasionally, or if you have fresh gears and bearings and bushings, SAE 90 is probably better.
For the non-synchro transmissions (I have a Clark 4-speed in my 1930), you need to use GL-1 (straight mineral oil) or GL-4, again refraining from use of GL-5 or GL-6. A fairly heavy-weight oil will slow down the gears during shifting to minimize clashing. There are two options:
(1) the old 600-W steam cylinder oil (essentially Pierce-Arrow’s "Special Compound") that you can get from Model A / Model T Ford suppliers at swap meets, but be sure you get the dark, smelly, viscous stuff rather than the translucent, less-viscous stuff also sold as 600-W but which I suspect is repackaged SAE 140. The dark, smelly, viscous version is probably equivalent to about SAE 200 in weight. I choose NOT to use this in my diff, but it’s fine in transmissions.
(2) big-rig SAE 250 straight mineral oil such as Texaco Thuban. Downside is that the smallest size available is a 5-gallon pail. You MIGHT be able to take a couple of clean one-gallon containers to a big-rig repair shop and get them to pump you some from a 55-gallon drum. The SAE 250 will be stiff for the first five minutes in winter in coastal Calif.
Perhaps someone from colder areas can add some info on fluids more suitable for their areas, or on semi-annual fluid changes where necessary.