Klonopin has a half life around 8 hours, just an fyi.
I should certainly help you sleep afterward, especially is you've no tolerance to benzos.
Klonopin has many different effects. It acts as an anti-anxiety med (good for stim comedown), a sedative (good for stim comedown), a skeletal muscle relaxant (also good for stim comedown), as well as an amnesiac (no real value here), and an anti-convulsant (not a bad thing)
all in all it should be great for stim come downs but you really don't want to become dependent on it. Using it for stim come downs once and a while seems ok but becoming co-dependent on stims and benzos is not a road you want to go down.
do some searching in the BDD forum, there's plenty of threads about klonopin if you want to learn more, many specifically targeted at klonopin's uses in combination with amps.
If you've no tolerance i'd recommend starting with 0.5mg or 1mg, work up from there if you need more depending on the dosage of amps you're coming off.
cheers.