i've try that sump settup,it didn't work for me, hard to fit the skimmer, heat and pump. with mh it was tough to keep the water level, i would get a ton of micro bubbles in the(display) tank when the water level drop.
i would just use an empty 10g, set you pump at one end and your in let(from tank) filter bag at the other end and skimmer(in sump or hang on?) and heat in the middle.
in a 29g w/ small bio load and a good skimmer + LR you won't need a refuge imo.