1960s Replacing sealed beam headlights. Convert to Euro H4? 1966 Eldorado

[Julien Abrahams]

Dear all,
Working on the '66 Eldorado.  This question is mostly for all you guys in Europe that use this forum.
While waiting for the local mechanic that works on old car to come back from holidays, I thought to investigate all the lights. It turns out that all the headlights (and a several other bulbs) are kaput, so I need to replace them. Now wondering what is best: buy new sealed beam lights (most likely halogen) or replace with Euro H4 halogen 'regular' headlights with a separate bulb and glass. 
I am planning to install two relays as well: one for the low beams and one for the high beams, just to make sure there is not more strain on the headlight switch.
Is there any major difference between the amount of light that sealed beam headlights give compared to separate bubls, or is it just that "light image" (how the light is being projected on the road) is different? 
As the car is more than 50 years old, it does not need to go through the annual technical inspection anymore (like "normal" cars have to in the Netherlands).
I see several kits on Amazon or Ebay but I am not sure whhich to buy. Help is greatly appreciated.