I am sure if you put the 32-3 in the Sundowner 50 with 6 cells it would haul. I was looking at the instruction manual and it isnt clear if a 6S pack would fit....I also looked at the weights....the Lil Toni at 8.25# (max weight) gives a wing loading of 24.5oz/ft^2, and then for the Sundowner at its max weight of 7#, gives a wing loading of 28.2 oz/ft^2. Not sure how that would affect the slow speed characteristics. Do you know what your lil tony RTF weight is with a 6S? The wing area on the tony is 775 vs the 572 on the sundowner. Thats pretty significant considering wing area is a large contributor to drag...speed being the biggest. I wonder how similar in design the two wings are. But assuming you could fit a 6S pack and the weight was right around 7 pounds, the Sundowner would have less drag and should be a faster plane. I wonder if the tony is that much heavier due to the glass fuse? Cause the overall dimensions are pretty close...same size wing...the Toni OAL is 9 in longer...