I was using a 10g fuge for my 90. I didn't have algae problems and the pods are great for wrasses and mandarins. If you have room for a larger one, oyu probably benefit more.
I opted for a bare bottom fuge with higher flow. I had one with a sand bed and the chaeto seemed to trap a lot of detritus that exhausted the sand. IMO, the refugium and DSB need different types of environments. Chaeto with moderate to high flow (preferably tumbling) and lots of light. DSB with no light, and fast moving water that prevents detritus from collecting on the surface of the sand.