Bro,
Why insist on beckett?
IMHO, Becketts are not meant to be small, reducing the size of the beckett will also compromised its performance. Thus you noticed most quality beckett are large.
For small compact places the best option is needlewheel, the needlwheel technology allows for smaller and more compact design without compromising on performance.
For your kind of tank and space, I would get the Deltec MC 500 or the Deltec MCE 600.
They are reliable, small, compact, consumes lesser electricity and will put lots of skimmer to shame. Plus they are around the price region of a good Beckett skimmer.