The upped sundials might throw off the muligan though. Also, the few towers would could mean you dont get any overdrives til it's too late. You need to get an OPP ready within turn two and 7 towers helps that, imo.
Even if you end up only with Sundials it's not a big deal since by turn two you'll be able to play something.
The overdrives are not a necessity to win especially because it's not meant as a TTK.
SoP already does boost the damage a lot. Besides, Sundials and Congeals give enough stall to make up for the little wait.
I have to admit though that I didn't make much testing, only like ten games?
However, if you feel like more towers are needed you can still replace a Chimera and Congeal giving you 7 Towers which should be enough