WisNewBee, You can use tossed out light weight Jenny Craig coolers. I have been having luck catching 2-3 pound swarms in them as they're bout the size of a deep nuc. I converted them to top bars w/ waxed comb guides as it adds the bees wax smell they love & usually helps make accessible straight comb(so far so good). I hang them up in trees when time or just leave on flat roofs w/ bricks on top.
I usually cut em out into 10 frame medium or deep after a month but waited longer on this one pictures below:Jenny Craig Swarm Lure Cut Out Transfer
Good luck on your swarm catches & if time Thomas Seeley has some info bout the subject of swarm lures in his book at libraries "Honeybee Democracy" Here is a link to some of his video's on NPR Science Fridays:Bee Swarm Videos on Science Fridays Feat. Thomas Seeley