We use the balls, both types, in our home dryer. They seem to work, But OH, are they ever NOISY!!!
If you use them in a Splendide, I think maybe 4 to 6 of them would be about right.
When we were using a Splendide, we found that being very careful about the amount of clothes put in it was the best way to control wrinkles. We would wash one suit of clothes (socks, underwear, pants, shirt) at a time. The only time we worried about mixing whites and coloreds was when we had new jeans. After they were washed a couple times, everything got thrown in together.