TUS scheme editor gives you complete control to modify a scheme. However superweapons as of now, don't follow all the settings in the scheme. For example you can't tweak super weapons crate probabilities. The settings for each super weapon is there but the game doesn't follow those settings.
oh, i completely forgot about that. quote from SchemeEddy v2.01 read me file.
Super Weapons
Super Weapons have a somewhat bizarre method in determining their crate probability rates. There are four conditions that must be met before a Super Weapon may appear in a weapon crate. (with the exception of a crate shower)
1. Super Weapons must be enabled in the scheme.
2. At least 5x as many regular weapons must have appeared in crates than Super Weapons.
3. At least 3 minutes must have passed since the last Super Weapon appeared in a crate.
4. If conditions 1 to 3 have been met, than there is a 1/8 (12.5%) chance that a Super Weapon will appear in a weapon crate. Which Super Weapon will appear is randomly determined from a list of available ones. A specific Super Weapon will not appear in a weapon crate if it has infinite ammo.
Note: Due to the nature of the Super Weapon probability method, I decided not to have my scheme editor factor in Super Weapons when determining overall probability rates. It is impossible to determine a fixed probability rate of a Super Weapon occurring due to the factors involved.