First off, my comments reflect the latest version of the flow chart that was in Stunt News several years ago. That was updated from the version of several decades previous.
As far as IC vs Electric in terms of using the chart, there is no difference on how to work through it. However, that doesn't mean they will end up the same!
But, there are differences between IC and electric in how they seem to trim out. The following are the significant differences I have found, and many other electric pilots as well: CG, leadout position, and engine offset.
CG....my data from years of using both.
IC balances at 22 to 26 percent of MAC, without fuel. Around 17 to 20 percent if a full tank of fuel is considered.
Electrics (mine) balance between 8 to 12 percent of MAC. That is a considerable difference!
Leadout position...IC is from 1.0 to 1.5 inches aft of the CG. I have even seen experts fly with the LO's in front of the CG. Oh my!!! On electric, they range from 3.0 to 4.0 inches aft of their CG. Again, that is a huge difference.
Engine/motor offset. IC "usually" is set at ZERO degrees offset. There are exceptions, but most use no offset. Electrics tend to use 2 degrees offset.
So why is this? The CG is related to the motor. Electric has around a dozen torque impulses each revolution versus the IC of one every other revolution. This once every other revolution impulse is much larger and may be contributing to the rate at which the plane can rotate, or not rotate. However my experience with 4 strokes opposes this theroy as they wanted the CG more forward as well. None the less, if you try to fly an electric plane with an IC CG, it won't fly up to its potential. The P-47 had the CG at 8 percent and still cornered tightly.
I have found that engine offset in an electric powered plane is a no brainer. I have tried over and over to attempt to use no offset, but the offset helps in so many places without any negative impacts that I just build it into the plane from the start.
Leadouts...similar to engine offset, I have tried over and over to make the leadouts work in a more "traditional" position. They will work there, and one could convince onesself that it was good, BUT, there is one, or two significent benefits of being aft. Number one is that aft leadouts resist the speeding up in consecutive maneuvers in a good wind. This effect is repeatable, and many other electric fliers that have tried this have found this same benefit. The other bonus is that it tends to damp the wiggles after corners MUCH better than with the leadouts forward. Give it a try, you might like it.
So, for the purposes of the trim chart, these effects can be incorporated into the bench trim before even hitting the field, thus reducing some of the trial and errors the chart can cause.
So, the bottom line is, I see no difference in the way the chart is used but the starting trim is different for IC and eletric.