Major Super-Strength has a built-in mechanics for this--you get a flat 4D, 10" ranged attack representing your ability to hurl massive objects. I did this for speed and ease of play.
If you want something more meaty, simply apply the Super-Club rules to your throwing attacks:
Small objects = 4D[1]
Medium objects = 4D[2]
Large objects = 4D[3]
In these expanded rules, Minor Super-Strength characters can hurl small objects out to 10". Major Super-Strength characters can throw small objects 15", and Medium and Large objects out to the normal 10" range.
You can give this a shot and let us know how it works.
For my money, I am happy using the simplified system in the base rules, but these more detailed rules shouldn't slow things down too much!