Even with a horizontal bulb he should get a decent spot. used horizontal for donkey's years with no problems. Daft as it sounds..you do get the odd faulty bulb...as you say..Osram are the best bulbs available for lightforce lamps imo.
no worries mate, i'm no expert, correct me if i'm wrong.....but I think the difference in the beam off the two different bulbs is one with vertical filament gives a tighter spot, whereas the other type gives a more oval slightly wider beam, or spot,
as you said........could possibly need a slight adjustment to the head of the lamp, or a dodgy bulb.....