This was first inspired secondhand by 69ron's method of precipitating fumaric acid out of spice containing FASW by bringing the solution to near freezing. What SWIM proposes is to simply freeze the entire mixture while still in the process of separating (after shaking vigorously for a good amount of time, of course), and after the bottom layer freezes solid, pour off the limonene (a similar such method has been proposed on the nexus long before the advent of limonene for extraction, but SWIM can't remember the details). Leave the remaining ice chunk to thaw, and if still cold and mostly undisturbed by the time its thawed, the excess fumaric acid should remain settled in the bottom; simply pop it back in the freezer for a little bit if in doubt.
There will be some amount of limonene left floating atop the thawed layer, but this could be separated out using a gravy separator (or whatever other chosen separatory method). So why not just use a gravy separator and then freeze? Well, SWIM finds it preferable to be able to eliminate the bulk of the limonene and the excess fumaric acid essentially all in one go, and because efficient use of a gravy separator can be somewhat of an acquired skill, this also seems to simplify that process. Lastly, waiting for a mixture to fully separate before isolating the layers can take some time, but this method only requires a waiting period for freezing and a waiting period for thawing; everything occurs in mostly automated fashion.
Note that this process is likely most preferable for the kitchen chemist lacking in a proper separatory funnel, but due to the simplification of three processes involved in use of FASW (waiting for separation after agitation, isolating the separated layer, and purification), it may be found useful even with a separatory funnel on hand.
SWIM will amend this to his own extraction tek and do a general writeup for the handbook, soon.