Bedrock Skyblock Height for level 10 zombie xp spawner

[cantpoophelp]

I have a level 10 zombie spawner and I wanted to know how high I need to build the farm.

 

[eaglehead_yt]

I THINK OF 23 BLOCKS SO IF MOBS COME DOWN THEY WILL GET DAMAGE AND WILL LEFT WITH ONE HEART SO THEN YOU CAN EASILY KILL AND GET XP

 

[SRMT]

I THINK OF 23 BLOCKS SO IF MOBS COME DOWN THEY WILL GET DAMAGE AND WILL LEFT WITH ONE HEART SO THEN YOU CAN EASILY KILL AND GET XP

Ty