First- I'll side with the rest here and say definately ride within your confidence level. If you're not comfortable to take the lane, then don't do it. You've got nothin to prove, so who cares. Just be careful on those sidewalks.

Second- I deal with a similar stretch myself. When/if you do decide to take the lane, the safest way to take it is WELL before this stretch. Let me illustrate. The wrong way to do this is as such; You're approaching this stretch and you notice heavy traffic (several fast moving cars, big trucks etc) coming up behind you. You think to yourself "I'll let this group pass and then "jump" into the lane when it's clear. By doing this, you're not giving much warning to any second wave of traffic that may come and you're not establishing any traffic "flow control" that you need to navigate a stretch like this. What happens is the first wave moves through at regular speeds. When you "jump" into the lane, any second wave must slow to your speed rather quickly. This encourages cars to switch lanes quickly and do that famous "swerve around" (switching lanes around a slowing car and quickly returning to original lane of travel) that drivers love to do. This just makes it hectic and dangerous for everyone. "Jumping" out in front of drivers just pisses them off, even if you do it with room to spare.
The best way I've found to do it is to claim the lane (when you safely can) well before a stretch like this and hold your lane well through the segment. Don't yield at any point. At first, it makes you nervous and you may feel like an a**, but this is why it works. By holding your line even with traffic, you are forcing that lane to slow and cars to switch lanes to pass. By doing so, you are essentially reducing the speed limit in one lane for a small stretch and raising driver awareness (for all lanes). This makes all drivers (even 3 or 4 cars back who cant see you) realize that there is something ahead they need to be aware of. People don't do the "swerve around", or at least do it more cautiously. If a driver is impatient, they can switch lanes, but have already slowed enough to have focus. It works and people are generally patient about it since you make your intentions clear.

Do what makes you comfortable. Just be safe!