There's a couple of old school (you should readily find them on the web -- Supertex for sure has appnotes on this -- now on Microchip's site) methods that provide limited current while also working equally well regardless of orientation of the 2-terminal device. These just use JFETs (higher voltage ones like 2SK373 or could use SiC JFETs?) or NFETs (like the LND150.)
Something like these:
simulate this circuit– Schematic created using CircuitLab
With the JFETs, the current will be what it is. But with the NFETs the current can be tweaked in with \$R_1\$. I set it to a nominal \$1\:\text{mA}\$ producing value. But when you get the parts you can work out the final details for it.
The NFET circuit's behavior will look about like this:
Works the same regardless of which way you flip it. So no worries. (\$V_{_\text{GS}}\$ for both devices is kept low.)
Here's Supertex's AN-D11 on the topic, for example.
You will need to worry about the LED orientation with respect to the voltage supply orientation. I probably would not want to start with \$100\:\text{V}\$, preferring to take it up in steps, if possible. But I'm not sure of your past methods, which you know far better than I. So I will let you figure out if this is workable, or not.