Which double bells to get and why

Heya,

I got cast iron bells 16, 24 and 32

I am unsure whether to get double 24, 20 or 32, or get one 40kg bell.

I can strict press the 32 for 7 reps. I want to get overall stronger, fitter more conditioned etc...

Unsure of what to do or where to go with this.

Ps any good resources other than Pavel to learn kettlebell programming, as I dislike following set programs for the most part.

Thanks!!!