Shorter is perfectly fine / great IF you’re not trying to make an ‘inverted down draft’ style stove. The only downside is that it doesn’t hold as much fuel all at once (not that big of an idea, IMO).
You might look at using a Unibit along with the drill for cleaner holes.
OR you can punch the ‘bottom holes’ with a church key can opener and use a hammer driven ‘punch’ for the top holes.
A hand-punch (Whitney is one brand name – think industrial grade paper hole puncher) for holes, but unless you get the extra big one, it’s ‘reach’ down the sides of the can is limited.
Depending on the size of pots your boyscout troop uses, a shortened coffee can may work better (and still nest)



