I am pretty sure that this has not been asked. As you all know, I am making a sand team and I want to know whether to use FerroT or FerroS.
Ferrothorn.
Ferrosseed is ouctlassed as F-Thorn has more offensive capabilities, access to Leftovers, better defenses than Ferroseed even with Eviolite, and is basically just a better version of Evioliite F-Seed, which would make sesne.
I suggest Ferrothorn.