>>>*K...Hope I am not too late. Now use a taper tap, same size as the threads since you need to save the threads.

Carefully feed it in until it binds, do not force it. Then back it out, clear all debris. Start again.

*Bit tedious but it works, be sure you stay aligned.

The so called EZ-outs work fine for bolts not frozen, but a simple screwdriver the right size will do the same thing and not spoil your weekend.

We do not allow hardened EZ-outs in the shop, they just break if the bolt is frozen.

Way too late to use the vibration trick, we take out rusted in place bolts with a simple peening hammer, (sometimes a mag tool) long story there, I will tell it if anyone has an interest..(My son and I have often taken out stuck bolts with our fingers, it always get a surprised expression from folks....)

Just use caution now, I can already see you have very good hands because you aren't off-center....*EB