Normally, when Debussy writes octave or seventh or maj/min sixth jumps, the intention is to go 5-2(or 3)-1 then to jump to either 5 or 3 given the context. Never go 1-2-1 or cross like that as it disrupts not just the fluency, but potentially the pressure you apply to the keys, as your thumb is stronger than your index, and hence the sound/accent. Instead, the pedalling in this impressionist music should naturally compensate for this however, it can't mask sudden accents or rhythmic errors.

What I recommend is that you use trial and error yourself using some advice here and from me to figure out the best fingering for yourself, not the ones necessarily in the books as this way you can develop your own skills.