I think your approach is what I'm probably looking for...a primarily manual setup but with at least one flash (SBxx or SBxxx?) with some autopilot mode for quick and dirty situations. So you have your 26s set as optical slaves, how are you firing your 28s, by cord or rf? And more importantly, would you recommend mostly 26s/28s for this kind of setup over LP160s, the other way around, or no difference?
I fire all with RadioPoppers, daisychaining multiple strobes to one trigger if in a multi-head configuration.
Personally I prefer older Nikon speedlights for this role. When you drop your LP160 five years from now how easy is it going to be to buy a tube? That said the LP160 was built-to-spec for the Strobist community. It is about everything you'd want in a manual flash, with (hopefully) all the livable corners cut to keep the price low. IF you buy one I'd only buy from Midwest Photo Exchange as they have a dog in the fight. Moishe from MPEX is the one who really got the ball rolling with LumoPro with their earlier strobist-targeted speedlights, and got LP to "eat" many of the early runs which exhibited issues.
I buy 26's and 28's because they can be had inexpensively. The 26 is larger than the 80 (80-DX) for the same guide number, and recycles a bit slower. This keeps the price a bit lower, and the compromise is one I can live with.
I see you caught on to the fact the 26s have a built-in optical slave, but I VERY rarely use that, I have plenty of receivers.
You've said "with at least one flash (SBxx or SBxxx?) with some autopilot mode" but mind only the 600, 700, 800, and 900 can be used i-TTL off-camera (CLS) (and ASSUMING your body can do commander mode). Old-fashioned A(uto) (thyristor) mode can get really wacky when your light is significantly off-axis from your lens, which renders it pretty worthless for off-camera usage. (Plus it is going to vary its output whenever you change the power on other lights in a multi-light setup - preventing you from tweaking one channel) With the 600 being easily available used in the USA for sub $200 and the 800 (2/3rds of a stop brighter IIRC) for ~$300 I wouldn't waste my time "autopiloting" with anything else.