How easy to go to dc lighting?

Hi, I've tried doing a search but can't quit find what I'm after so here goes.
I did find on here To use a LED headlight I have to go from A/C to D/C. Is this as simple as fitting a 4 way bridge rectifier to the high and low beam wires from the switch and then onto the bulb holder ie AC in DC out and then fitting a capacitor to the DC side to take out the micro flickering thus making the light brighter?
This would then lead me to asking which type of bulb will give a focused pattern?
Like I say I've looked on here so I'm not going along the path of not doing the searching. Thanks
I did find on here To use a LED headlight I have to go from A/C to D/C. Is this as simple as fitting a 4 way bridge rectifier to the high and low beam wires from the switch and then onto the bulb holder ie AC in DC out and then fitting a capacitor to the DC side to take out the micro flickering thus making the light brighter?
This would then lead me to asking which type of bulb will give a focused pattern?
Like I say I've looked on here so I'm not going along the path of not doing the searching. Thanks