Last weekend. Really enjoyed it a lot

I know I googled and researched this. From what Ive seen, my 65 firewall had ports for steering, brake, clutch. It has a bulkhead connector for feed harness, and below it has ports for speedo cable and parking brake cable.

I'm trying to run several more wires through the firewall for new gauges, and I'm looking for the cleanest way to go about it.

If this was a less original / more custom application, I'd just cut/drill a hole next to existing bulkhead connector and put a Deutsch or milspec bulkhead connector there and just run my engine bay wires there.

When looking at firewall now, I see places where maybe there is a knockout for some unused port or accessory or something.

I hate idea of having to drill a new hole. If I must, I will, but if I'm passing several wires through, what would be the best way of sealing that? A tapered rubber grommet with enough ID to pass wires through and silicon to fill gaps between wires?

Thanks for any pointers