Most efficient Bridging method?

[Kenundrum]

So I've got a silly question. In short- what is the most efficient way to bridge multiple FGT interfaces.

Hypothetically, you have a large handful of EOL FGT60Cs, and someone suggests using them as "dumb" switches/hubs temporarily instead of buying actual switches. Pretty much this hypothetical project just needs to extend a few ethernet runs past 100 meters for a month or two while a permanent wiring solution is built. The data going across the links is out of band telemetry that is "nice to have", so it doesn't really have a need to be up 100% of the time.

How would you bridge the interfaces together to make use of them most efficiently? Software switch or transparent mode? Obviously all the security features would be shut off to keep CPU available.