How to replace commas with white spaces in a csv, but inserting a different number of space after each column?

I have a file in the following format: s1,23,789 s2,25,689 and I would like to transform it into a file in the following format: s1 23 789 s2 25 689 i.e 6 white spaces between the 1st and 2nd column and only 3 white spaces between the 2nd and 3rd column? Is there a quick way of pulling this off using sed or awk?