The opener I use:

B2 > M > B > Swift + Fester > Shadowflare > Rouse + Spur > R2 > Pot > R2 > RS + Pain > R2 > Fester + DWT > R2 > Aether + Enkindle > R2 > 3D > R3 > R2 > Fester > R3 > R2 > Deathflare

Advantages: no clipping, ASAP Shadow, pot hits Pain + Fester + DWT Fester, get into DWT within 7 GCDs which helps if you pop Litany on the pull, can be a final R3 > hardcast Deathflare if you have Selene or massive SS like these dumb i210 pants give.

The opener you use:

Bio 2 -> Miasma -> Bio -> Painflare -> Fester -> R2 -> Swiftcast -> Rouse -> Shadowflare -> Spur -> Raging -> R2 -> Painflare -> Aetherflow -> R2 -> Pot -> R2 [Bio is dropping] -> Enkindle [delay] -> DWT -> Tri-D -> Fester [10-11 secs left on pot] -> R3 -> R3 -> R3/R2 -> Fester [1-2 secs left on pot] -> Deathflare [before pot ends]

Advantages directly compared to mine: Pot hits DWT Fester X2 + Deathflare

Disadvantage directly compared to mine: Trading a Fester for a Painflare in the long run, less stacks to use on Bane or Painflare or staggering Fester to use after initial DWT, some clipping (which doesn't matter much for SMN unless it cuts you off from something), lose an attack in DWT, slightly slower DWT activation which may or may not impact you based on TA/Litany (could also benefit you I suppose!)

The opener I use, I never really intended for it to catch on as something people use, was just something a buddy and I whipped up after comparing our ARR opener with Hai Hai's opener and merged them. It could probably benefit from some tweaking but there will always be downsides to the compromises in some ways so I haven't really found something that's just straight up, this is better period (in which case I would start using THAT opener).