After getting a couple of large holes in a brand new tyre (Panaracer 700x38c GravelKing Slick Tread) that couldn't be sealed by either the tubeless sealant in the tyre, or traditional plugs, I decided to experiment with a hybrid approach.

Process

After purchasing an inner tube repair kit, I removed the tyre, and cleaned the sealant off. I then followed the instructions to repair an inner tube, but on the inside of the tyre:

1. Sand around the area.
2. Apply rubber cement.
3. Allow to dry for 5m.
4. Apply patch and press firmly into the rubber sealant.
5. Wait for some time.

Once the cement had bonded the patch to the tyre, I re-seated the tyre on the rim, applied sealant, filled with air, filled with air again after fiddling with the tyre, enjoyed the snapping sound of the tyre seating, rotated so that the sealant was initially evenly distributed but would settle over the two holes, and waited.

+24h
The tyre had dropped to ~50% pressure (2bar). I spun the wheel to distribute the sealant, re-inflated to 4 bar, and waited.

+72h
The tyre had dropped to ~3bar. I spin the wheel to distribute the sealant, re-inflated to 4 bar, and waited.

+96h
The tyre had dropped to ~3bar. I spin the wheel to distribute the sealant, re-inflated to 4 bar, and waited.

+120h
The tyre remained at 4 bar. I took it for a gentle, experimental 10km ride, and it held.

Observations

The tyre is once again rideable, whereas before it would only have been rideable with an inner tube.

I think this could be repeated in the field, if one had a couple of C02 cannisters to spare, and would have probably stablised faster due to the sealant being distributed by riding. It wouldn't be faster or more reliable than an innertube.

For me this falls in the category of an interesting experiment, but ultimately in the category of just because I can, should I..? I'm mindful of what a catastrophic failure could look like (the tyre splitting), and that the cost of a new tyre is about $50. I'll ride it until my replacement tyre turns up, and assess the repair then.

Update at 200km+

All good things come to an end: the patch started to bulge out through the hole in the tyre, and ultimately popped as I was boarding Amtrak. Thanks to the sealant, Finish Line, I was able to ride home by rotating the wheel so that the hole was covered by sealant, and slowly re-inflating it. It wasn't my fastest ride, but it got me home with minimal fuss, which is what matters.

Conclusion

One can patch one's tyres with inner tube patches, and it works. It works well. But it's not a durable solution. For that, a tyre boot should be used, which is a much larger, more durable patch, or the tyre should be replaced, depending on funds and ethics.