Extra coning will only bring on unwanted trim changes, but once trimmed will be fine if its not too great.
It adds no extra stability other than making the mass of the fuselage further away from the blades. The longer the mast the more stable it will feel but the less effective the roll control is.
The flatter the disc the less roll trim you will need to add which makes ROG far easier to do.
Well that is what I have found.
Here is a video that I made a few years back