Sadly they're more trouble than they're worth.
Here's the measurements of the Neo10 in one of Danny's Super Mini baffles:

With a 2nd order network:

Here is the GRS in the same baffle:

GRS with same 2nd order network:

It's a very different curve and will require more parts to control the rising response.
The one major issue with the GRS clone is that it is missing the corrugated suspension that the BG unit has. Which means that it has far less power handling, especially below 200Hz.
The Radian LM10 will be a much better option, but we will need to design something new for it.
https://radianaudio.com/products/lm10n-wide-band-planar-ribbon-transducerWe've measured the GRS 3" clone as well and it does okay. But we have only looked at one so no idea how consistentcy is on them.
I dont have the measurements saved on it at the moment.