Finally, about SMN DPS, lets look it over
Bio: 40x18(6) = 240
Bio2: 35x30(10) = 350
Miasma: 20 + 35x24(8) = 300
Lightning: 30 + 35x18(6) = 240
1130 total potency. With perfect contagion, lets give that a 33% increase in damage
1500

so far, so good, as these spells have fairly strong combined potency. The average length is 22.5 seconds, and lets say Contagion is used perfect every 60 seconds adding 13s/2 = 7 seconds generous (since it won't be applied with full dot uptime, and is not always available). So, average dot time of 29.5 (call it 30) seconds in 4 GCD's so that leaves you 20 seconds of "filler" time in a rotation, or 8 ruins (80 potency).

so, in 12 GCD's, you have
4 GCD, dots with contagion = 1500
8 GCD's Ruisn 8x80 = 640
2140/12
= 178 potency per spell average with perfect cooldown

this ignores Fester, lets add in 3 fester per minute, 1.5 per 30 seconds and its off GCD, so
2140 + 450 / 12
= 215 potency
adding in perfect pet, say 900 pot

= 290 potency per GCD,