String Recommendations for 5-String Bass

[Overgeared]

I’ve just picked up my first 5-String bass, a Schecter C5, which I’m loving. As I play Rotosound 66s on my Jazz (standard gauge), I put the equivalent 5-string set on the C5, but the feeling when I pluck is different. It’s difficult to describe, but when my fingers come to rest on the string below after plucking a note i get this kind of dead thud feeling in my finger, and i seem to hear a similar overtone. Needless to say I don’t get any of this on the 4-string.

 

My question is, is this caused by my technique, in which case what changes need to be made to accommodate a 5-string, is it just because it’s a longer scale, or is this the strings, in which case what strings would you recommend I try out, and in what gauge, for 60s/70s/80s rock?

 

Thanks