Alright, I personally use that blissey set myself, or a variation of that. Now, you are focusing on evasion to avoid damage while toxicing them to death. Now, I personally use minimize AND substitute. Substitute makes me immune to being paralyzed confused poisoned or anything else. And if they are able to move first, and status me before I am able to use substitute. I have nature cure so I can switch out and deal with whatever Pokemon that is there. Now, if a poison or steel comes around, I simply switch out to a ground type. ground is super effective against both steel and poison. My ground type of choice is garchomp. Now, here is what can play out. blissey with bright powder for additional evasion, uses substitute, the Pokemon either attacks, lands, and doe enough damage to break the subsitute. In which case you subsitute again and hope for them to switch use a status move or miss with the bright powder. then you use mimimize the moment you get a miss, or toxic. Some moves like Arial ace never misses, as such you should watch out for it. But a move like swift, that is a special attack blissey has high health and special defense its likely that swift would not break the substitute, as such not a threat. A physical attacker that hits hard enough to one shot blissey. Now, you could remove toxic off blissey entirely for a sleep move instead, and use toxic spikes support on a different mon. and those turns of sleep to set up a bit better. There is a lot of variations you can do with this, I personally like it but it is quite luck based. the enemy needs to be lucky to win if you set up right, or bring steel or poison types.
