That butt connector you have looks like it has some seals in the end ?
I don't know what your crimper is, the one i have from Greenlee (KP1022D) and it rated 10-22 Ga.
Soldering the spice is ideal but not the connector, in areas of vibration like on an alternator cracking can be an issue.
I was taught in these areas a good crimp is preferable.
I understand your problem, no heavy soldering equipment and you sure don't want to be near the rest of the harness with a blow torch.
Quote:
BMW didnt think it was worth soldering
I always thought solder was better until i learned different from an electrician, crimps are fine if they are strong.
You may want to get a stronger crimp tool though if yours is too light.