Replacing a UPVC Window

[Jupiter01]

Looking to replace an existing window and had some questions please.
1. I intend to measure this from the outside and in 3 different places for width and length and then record the smallest measurement less 10mm. Correct?
2. The current window has a plastic sill. This may get tricky when measuring the height as the tape measure will have some flex in it. The sill has horns around the brickwork. Can you offer any advice for this please.
3. Which type of screws should I use for the new window and how much need to bite into the brick?

Not had to do this in the past and appreciate your guidance. Thanks in advance.

 

[diy_fun_uk]

Modern UPVC windows: DIY window measuring sheet

Fitting UPVC Windows | Installing UPVC Windows | Eurocell

 

[Jupiter01]

H

Modern UPVC windows: DIY window measuring sheet

Fitting UPVC Windows | Installing UPVC Windows | Eurocell

How do these methods cope with the vertical measurement when there is an overhang (horned window sill) on the window sill? Naturally, the tape measure would be arched towards the top edge of the window when measuring vertically? I tried to overcome this by drawing the top window line across the brickwork (using spirit level) and hence measuring straight up from the sill without bending the tape measure but can't see how I can measure the vertical central line with any degree of accuracy.

The width measurements were straightforward.

Any thoughts?

 

[diy_fun_uk]

H

How do these methods cope with the vertical measurement when there is an overhang (horned window sill) on the window sill? Naturally, the tape measure would be arched towards the top edge of the window when measuring vertically? I tried to overcome this by drawing the top window line across the brickwork (using spirit level) and hence measuring straight up from the sill without bending the tape measure but can't see how I can measure the vertical central line with any degree of accuracy.

The width measurements were straightforward.

Any thoughts?

Tbh I'm not an expert and would be reluctant to give the wrong advice. Someone else might come along with how to. Can you post a couple of pics of the window and showing what you mean?