There is no "one and only" way of shading round shapes (although there are "no ways" - ways that
must not be used, like gradients), but these days the 45-degree rule is becoming more and more common, and in fact becomes something of unofficial standard.
Basically, typical for Shipbucket would be use of just 3 shades for such simple shape (more could be used if there were some overhangs and the like, but let's leave it for now - and some artists insist on using bit more shades, like 4-5, but that's a bit of gray area - the
original style would use just 3).
An object with circular cross-section shaded according to 45-degree rule, would have
approximately rear 1/6th shaded, front 1/6th highlighted, and middle 4/6th in the base shade.
For something with ellipsoid cross-section these proportions would be different, and it would depend on actual shape of that ellipsis, but as a rule of thumb I'd suggest shading and highlighting approx. 1/8th each of the object's "length".