A 5th gen Civic clutch master cylinder was chosen as the hand brake's cylinder. This was chosen simply because the fluid reservoir was separated from the MC.
An adapter was fabricated to allow the brake hard line to bolt to the clutch MC input where the reservoir line used to go.
The original handbrake cover has to go to make room for the hydraulic one. You need to keep the original cable operated handbrake if you want to keep the car as daily driver. Hydraulic handbrakes shouldn't be used as parking brake as the extended pressure would damage the seals prematurely. Here you can see that i designed the hydraulic lever to sit above the original lever. Be very careful when you drill the holes on your chassis for the brake lines access and mounting bolts. You don't want to damage any existing brake lines or even fuel lines with the drill bit.
Hydraulic handbrakes are basically clutch master cylinder placed somewhere along the rear brake line before the T-branch on the rear axle where the fluid gets distributed to the left and right drum brakes. The line from the front brake MC is plugged into the clutch reservoir line input and the MC's output gets plugged to the T-branch.
This is a comparison diagram of the original brake line plumbing vs hydraulic handbrake plumbing. Note the Female to Female flexible line (blue color). I used the flexible hose that goes to a clutch slave cylinder, commonly found on Toyotas. This was needed because i need to extend the original brake hard line with another 100cm hard brake line to reach the hand brake's MC. I could only find male-to-male brake lines so the female-to-female flexible line is needed.
Bleeding the brake line after installation is done like normal brake fluid bleeding. You don't need to pull on the brake lever to help the bleeding process.