LO Sludge Bomb is hard to take, but most sun teams can't get rocks up without Phan or Duggy, so by eliminating SR, it should be easier to wall if you preserve Rotom-H. Since Gene and Venu are so common on sun teams, it really makes it hard to do much, especially since Venu needs +2 to actually do stuff, and a LO, which LO damage is not good for Venu when its LO + Priority. Just mentioning it since most Deo-D teams have priority abusers... Not saying it has to be on Deo-D, just that ROtom-H fits well on them.
Walls Venu varriants of:
Giga / HP Fire / EQ / Growth
Giga / HP Fire / Sleep Powder / Growth
sludge bomb is tricky, but ultimately can't do anything without +2