Easiest/Cheapest way to stop breaks squealing?

Brake bias is not typically adjustable on a road car. There's a brake proportioning valve to compensate for axle loading (and it gets exciting when that seizes, as I've found out!). Plus on most cars built in the last 20 years or so will have ABS which will prevent the rears locking.



Rear discs have been pretty common in the UK for the last 15 or 20 years... not universal but more common than not, especially on anything bigger than a small hatchback.

Copper grease will help on new pads

You'd need to change the bias as the front brakes would be significantly more powerful than they were previously. Therefore it's quite dangerous and you could lose control of the vehicle under heavy braking.

Or you could do them both at once and be done with.

Your braking force shouldn't be affected until the brake pads are very worn, therefore changing pads an axle at a time will not effect your brake bias. I'd certainly get pads and rotors changed and axle at a time though, generally pads last 2 or 3 times the miles as rotors, and back pads last twice as long as fronts.

Also you do understand how much of a complicated a job it is changing a drum braking system over onto a disc brake? People don't normally do that!