valve springs - recommendations

as it turns out that i will go on further with putting a 5.2 magnum into the 65 B´cuda and let the 273 as it is at the moment and store it away...it leads me to the well known weak point of stock magnum valve springs...

what do the members who drive magnum engines here use ?

what will be the best solution without machine work on the heads ?

cam will be more on the mild side (approx. max 0,500 lift maybe later going forward with a custom grind or a whiplash cam)

so let´s bring out your recommendations, suggestions and experience with valve springs...

(furthermore pls keep in mind that in Germany i wouldn´t have the option to go to a junkyard to pull parts there - you would not find any Dodge Dakota or an old Chevy there)