Now now Gentlemen... The poor chap is looking to you two in particular to help him out with his problem.
Sorry Dave (and regards to the newbie) all I can envision is a pile of parts in an oil puddle in the middle of the floor, and the poor guy scratching his head wondering what, were and when it all went south.
I disagree with the pick of a low temperature model, this is a medium temp application, I'd also agree to say that out of the box, a 1/4HP unit is too large without the adjustment to the capillary size as mentioned. ( you'll flood the evaporator coils & get liquid refrigerant back to the suction valve and damage the compressor)
also keep in mind that Sliders, be they Ideal or Glasco, have a problem keeping there evaporator coils in contact with their tank walls, as they fall away from inside of the tank wall, [but are held in close proximity to the tank by the insulation], they the can't exchange heat efficiently, so the box temp goes up, the compressor long cycles (runs forever it seems) & the suction line frosts back to the compressor.
But hey! Nothing that a hammer, a shot of freon and a spray can of semi-gloss black paint can't fix.