Is that gap of performance between the 2.2 and the 2.6 larger than between the 2.6 and the 2.9?
No, there is a gap between 560x and 555x that shows on some benchmarks. CPU wise they are literally identical inside of macbook case, with actually 2.2 beating 2.6 when close to thermal limit.
I agree with this sentiment, but OP says he will be buying from Best Buy, so assumably they won't have BTO options in stock.
I missed that, yeah, in that case the 2.6 stock config makes more sense.
How has the heat been for you doing basic stuff like web browsing, youtube etc. Because I need Chrome dev tools I would need to be on chrome most of the time rather than safari (not ideal I realize). My current 2015 15" MBP with integrated graphics can get really hot at random times (just browsing particularly javascript heavy sites). I had a Macbook Air previously that really spoiled me for quiet cool computing but I need as much screen space on the go as I can get. Is the 2018 base 15" at least usable on your lap from a heat perspective? Are the fans distracting in normal non-pro use?
I have 2017 Air, and when chilling out, browsing etc there is no difference, no recognizable noise coming from the laptop, no heat. At about 20W the fans become noticeable, and definitely loud at 45W - 50W (100% CPU usage) but compared to the recent laptops I had (P34, XPS15, Sager) the noise is much lower and .. ehmm.. easier on ears, I can't really explain that, looks like they did something to the blades of the fans so that the sound frequency produced is not annoying. But for the sake of future generations that you hope to spawn, I wouldn't keep it on your lap above 30W of power usage, the bottom gets warm.
What are those JS heavy sites, I can have a look and let you know.