Here it is:
Comet - Manaflow Band - Transcendence - Scorch- Second Wind - Unflinching
AP AP MR
Corrupting potion
Q -> E -> Q
Q max -> W ->E
In this matchup it is crucial to time your Q with your CDs to maximise damage efficiency
Q (10s (lvl1))
comet (20s)
scorch(10s)
corrupting (12s)
You want to Q on scorch CD (every 10 s) to poke heimer and last hit minions
Once you have lost some Hp & mana then when you use corrupting you should instantly Q for the burn damage & then as soon as your Q is off CD you should use it again (this way you get 2x the corrupting burn dmg) there is a 2 second window for this so it is pretty easy to do
Go for an all in once heimer is weak (around 40-50% hp)
one of Sylas' hardest matchups (extremely low pickrate though)
even if u ask for jng to come he is likely to go 1 for 1 due to his turrets being so potent
Farm lane you will be shoved in so you should alert your jng before hand to stop heimer from snowballing from river skirmishes
Look to rush Lost chapter

Haven't vsd heimer much as he has a low pickrate so I don't have much experience but im planning to add more matchups tommorow and ill update the guide.