I am hoping that you are able to add an outer perimeter to the support structure.
I would like to see this to be a setting that adds a perimeter to the support prior to the dense support layers.
Able to set the number of layers preceding the dense support layers along with the speed.
the reason for this is that the outer edge has gaps and the dense support layer has nothing to support it and there for it bunches up on the nearest support there is..
There are multiple paths you can take to avoid this problem, sorted by how much more filament they will use:
First of all you could try to rotate the support angle (under the support tab) from 0 to something that fits your model, if it's just needed in one particular direction. If you only need to support overhangs in one particular direction this is the easiest way to go. Just align them such that the top layers are printed perpendicular to the support - emulating the perimeters you ask for.
You could also build your support as a grid structure. To do this just add another angle to the support angles list. Have this angle be perpendicular to the already existing angle. This way you don't use more filament but get a very strong support and the furthest a perimeter can be from your dense support layer is one layer. This can also be used to generally strengthen support structures - just add 5-8 zeroes as support angles and then add one with 90 degrees. This way you get a clean support but have the added strength of a perpendicular layer every 5-8 layers. I found that this greatly decreases wobbling in high support columns.
The next very easy solution would be to just specify more dense support layers. I use 4 upper and 3 lower layers at 85% infill with 35% infill for my supports. In addition I have 0,0,0,0,0,90 as my infill angles. That's at 0.14mm layer height - your settings may be different. 2-6 dense layers is probably the way to go though.
The most filament and time consuming thing to do would be to increase your support infill percentage. A good starting value here will be around 30-40%.
If you would like you could post a factory file with your settings and models and we could work out how your settings could be tweaked.