Alright so apparently no one seems to understand this simple concept, so I'm gonna post it here.
Roamers: When you spawn at the beginning of a round in rollout phase, DO NOT ROCKET JUMP until your Medic buffs you to 300 HP using Crit Heals. You make our lives way harder and you will never get to Middle healthy and keep putting the whole team at a disadvantage before Mid even begins.
I repeat, STOP ROCKET JUMPING IN SPAWN BEFORE THE MEDIC HEALS YOU TO 300 HP!
Pockets: Blast yourself down to low health (regardless of whether you are using shotgun/gunboats) and walk to Mid with the escape plan equipped. Just before entering Middle, switch back to your primary and STAND STILL so your Medic can arrow you, and then heal you to 300 HP for the Midfight.
Thank you, the quality of TF2 Center 6s has increased by 150%.
Every Medic player.
P.S. Please watch this and learn: https://youtu.be/hd0qIp1zF9U?t=1m