You may be able to drop the seat height by drilling a new hole(s) through the lower rear shock mount. Check out the two positions offered on this KTM replacement shock.
https://www.chinariders.net/showthread.php?t=31860
If your lower shock mount is similar, you can drill new holes to get the swingarm closer to the seat. A half inch shorter will yield 1" or more lower at the end of the swingarm. I am no geometry major, but it is a triangle. Maybe I can figure out the math with the help of my math genius son
The other option (or use both!) is to make two doglegs that are longer to connect the linkage to the lower shock mount. This is a viable option, but for me, not so easy because the two doglegs are welded to a cylinder. It is a "unit". I would have to fabricate a new one.
On the new lower shock mounting holes, they must be no larger than the pin diameter of the bolt that goes through the original mounting holes, or the pin will move every time you hit a bump, or get air. A bushing could be used to fix that, but drilling the right sized holes is a better plan (and they have to be parallel, so I will use a drill press when I finally get around to it.