I've just bought some cheap Avid speed dial 1.9 V brake levers, and was wondering about the small red dial on the front of the brake. It's an adjuster which moves the position of the cradle that the "barrel shaped bit on the end of the cable" slots into, which I'm assuming adjusts the leverage of the brake. How have other users got their's set up? Do they only adjust power or do they alter modulation as well? Any advice gratefully received.

It does adjust the leverage of the brake lever. Basically I adjust mine so that both the front and rear levers have about the same feel. As there's generally more friction on the longer cable run to the rear, turn the knob anticlockwise to increase the leverage for a softer pull. I doubt it affects modulation.

Yup, it adjusts the leverage.

Away from the bars: quicker action, less braking force.
Towards the bars: slower action, more braking force.

For me the trick with rim brakes (especially when wet) is to get the pads to key into the braking surface on the rim ASAP so they can start working, so I adjust them all the way out for maximum inital bite.

If you need more power, the first thing to do is junk whatever pads you're using and get some WTB Razors (the red/black ones). I've tried loads of pads and these are easily the best.

Next get some decent cables (ie. non-stretchy), I'm using Clim8 but there may be better out there.

Finally, just squeeze harder (I have got freakishly large hands though...)

Can anyone tell me what the advantages and disadvantages of Discs are I was either going to get, Formula B4 or avid arch rival v-brakes with speed dial 7 levers??????

Wot do you think

I think you're taking the piss.

Let MBUK decide. They really are experts.