Nero Vision doesn't have my DVD's required speed in it's options...

I have DVD+R DL empty discs and they are 240 Minutes 8.5GB. On the discs themselves it says 2.4x speed.

But when I use it through Nero Vision 4, it ALWAYS fails. I try burning with DVD+R discs of 120 Minutes 4.7GB with 16x speed and it always works. I did a thorough search trying to find out why it works on 4.7GB and not 8.5GB discs.

Then I stumbled onto the speed of the burning process. On the 4.7GB discs I have the option to burn in 4x, 8x, 12x, 16x and Max. But on the 8.5GB, it only allows 4x and Max. My discs say 2.4x but I can't go lower than 4x in Nero Vision 4. I have a feeling this is why it always fails on the 8.5GB discs. Maybe the program is trying to burn too fast for the disc and it fails?

Is there any way I can go lower than 4x or am I really stuck?