This is a 1D map (in Kalmaker), so consequently there is only one variable figure to alter.

Reference angle is basically the delay factor between TDC and the point at which the ignition trigger switches.
It only needs to be changed when using another type of engine and/or distributor/crank trigger, which is not suited to the calibration you are using.

Using Hall Effect Distributors
From doing many conversions, the thing we have found is that the position of the pickup/trigger in relation to the distributor lead posts is the thing that effects things the most.
The Reference Angle has to suit so that when the trigger fires, it coincides with the rotor button so that it fires very close to the distributor post.
If this doesn't happen you will get cross-fire between the adjacent distributor post, which causes the engine to run erratically. This may be at idle or higher in the rev range.
Twisting the distributor doesn't help, because the pickup is also mounted in the body along with the posts, so this only changes timing.

To set up an unknown distributor, the aim is to get this balance right so that there is near equal amount of timing range on either side of the post. If you have minimum advance of say 10 degrees, and maximum of 40, the total sweep is 30 degrees. Divide this by 2 and that gives you 15 degrees.
Add this 15 degrees to the Static (Initial or Setup) Timing position of 10 degrees, and you now have 25 degrees that the rotor should fire directly in line at the distributor post.
If you now turn engine (manually, not running) and set crank position to 25 degrees BTDC, and then position distributor so that rotor is pointing directly at No. 1 spark plug post, and then lock distributor in position. This will be your new static/base timing mark.
If you now turn engine to TDC, you can now mark on distributor body where TDC is.
The Reference Angle is the angle between this mark ( at TDC) and where the Rotor button will be  pointing, when the Trailing Edge of the Chopper Wheel switches the Hall Effect Sensor. It switches  in approximately in the middle of the sensor. You can check this switching electronically, by performing the Hall Effect Sensor Test as shown in the Workshop Manual.
NOTE, Remember, that distributor degrees needs to be doubled from crankshaft degrees.

Shown here, is a V8 VP Commodore distributor, with protractor ring (in crank degrees) showing the locations.
The first shot shows the dizzy post at 20 BTDC. Notice the shaded sweep area of the timing range and how close it is to post.
The second shot  shows rotor at TDC, and you can just see the Leading edge about to exit the sensor.