I learned long ago that when something is in question, like this, then it's always a good idea to bring your variables under control & Bert has it covered fairly well.
Pop the drums & have a look at the linings, if they are 'in service' items you can see how much of the surface has been in contact. If the contact is full length, then it's all good, move to the next step.
Check wheel cylinder operation. All good?

Then while the drum is off, ensure that the adjuster has full & free movement. In other words, ensure it will actually screw all the way in or out. If not, remove & fix.
Return adjustment to fully out position.
Disconnect handbrake at wheel cylinder.
Ensure that wheel cylinder slides along the slot in the backing plate. This is a single piston design & when the brake is applied, the piston pushes one shoe & the wheel cylinder is free to slide back & push on the other one, so make sure it's got freedom of movement.
Refit brake drum & wheel.
Adjust brake while moving wheel a little in both directions. This will help position the shoes correctly when the shoes finally touch the drum. Adjust carefully to ensure that all un-necessary slack is removed. Do both sides the same.

Loosen off handbrake adjuster & refit rod or cable then adjust handbrake. [ensure that the cable is free to move over the full range of movement]
Bleed brakes if necessary.

If everything is checked & found serviceable, then adjusted correctly, then it WILL work as advertised.
Road test in both forward & reverse & check adjustment again to pick up any settling into position that the brake shoes might still do.

Yep, that's what I have done several times in the past. It's a pain to do it all but my brakes always gave of their best & never gave me any grief once they had been properly serviced & adjusted.