Looking for heatsink detailed dimensions from ebay module

[Fire Doger]

Hello,

I am making a dev board for practicing control theory (MPC mainly) based on temperature using peltier.
I have found some cheap modules on Ebay to use their parts but unfortunately some information (Holes pitch in heatsink) are missing, I want to mount the whole setup on PCB to be more robust.
Unfortunately waiting 30 days for heatsink and then 30 days for pcb isn't a solution. I could make slots rather than holes but I was wondering if anyone knows the hole size and pitch to avoid it. Sellers doesn't help...

Thank you,
Below is a pic of what I want to do.
Stefanos