I take off my steel crampons for the cleaver. Just clip them somewhere, no need to take the time to put them on/in your pack.
Just takes a few seconds. I've seen too many people stumble and step on the rope with poons on the cleaver. Plus, up higher on the cleaver is a good place to change layers etc..., you'll probably take them off anyways.
my $0.02 :
I'm a lightweight packing freak, but I still don't think aluminum poons are up to snuff. I don't use them ... yet. You can bend the teeth by walking on ice or kicking steps. You really want to lose a point on Rainier? They are dullish too. If the snow your on takes crampons that dull, you probably don't really need to wear them (knocks on wood). There are some minimalist steel poons out there that aren't obsurdly heavier than aluminum ones. I vote for getting lighter boots and using good sturdy crampons.