Hi Vilas,
"So how to manage that at 4miles and yet be stabilised at 3miles(1000ft)?"
That is a very valid question.
Where I operate, If given ATC speed control you have down to 500ft to get the speed parameter inside the stabilized approach criteria. ONLY speed, and ONLY when ATC has given speed control.
About the speedbrake use and VLS etc. I will tell you how I do it, and this is not more than that, my personal technique/idea/whatever:
First I try to avoid doing it unless really required. Saying unable is of course a more than valid option.
Then, when using the speed brake you donīt have to go either 1/2 or full, a gentle gradual extension monitoring VLS and the speed trend arrow is better. I have found that in the end no more than around 1/4 should be required and also that once the speed starts going down you can put them back in.
In the 330 I think it is just about putting some dirt on the wing and kind of "breaking the inertia". There are a few seconds between pressing for managed speed and the speed really starting to go down that are the problem and can be crucial in order to reach Vapp before 500ft.
Iīve never needed to use them on the 340 with CONF FULL. I think this comes to be more an issue of the 330.
Cheers!