Enough port area?

[THATpurpleKUSH 5,000+ posts]

You want as few bends as possible when designing a slot port

 

[hispls 5,000+ posts]

What's the most common method of port design in your typical "L" shaped box when the port is longer than the box allows?
Here's two different styles i've seen, (rough sketched this to show you what i'm talking about)

The second.

If I can get away with a 4inch round port that would be easier for sure...I just don't know if that would be adequate...I would rather error on the side of caution and have more than enough, than not enough. WINISD recommends 2.5cubes tuned at 23hz!

I really believe 4" round is plenty for 600W single 12. As you say going too big won't get you in as much trouble, at the same time you don't strike me as the type that is going to be even pushing your 600W much even so even if you were right on the edge of on-paper being inadequate I don't think you'd have any issue real-world 99% of the time. You need pretty high port velocity to get chuffing noise, flared ports can help with this and you need to displace the entire volume of air in the port before you break woofers which you absolutely will never do with a 12 spoke frame 12".

You want as few bends as possible when designing a slot port

Definitely this.