I�d love to get an e-mail group together on BOSS settings. I have two stainless BOSS equipped Model 70's, a 7mm Mag and a .270. I've also had a problem finding good settings for some loads, especially the lighter loads. I've used trial and error and reached the following conclusions about factory loads in my guns.
The 7mm doesn't shoot the 120 gr. loads really well at any setting. Disappointing, but an experienced 7mm Mag shooter suggested I start experimenting at the heavy end of the available loads and work my way down. I tried 175 gr. Fed. Prem. and Win. 160gr. ballistic tips. The gun shoots the 175�s well at a setting of 10. The bullet doesn't stabilize until about 200 yrd.s so it shoots as well at 200 as at 100 with avg. groups at 300 @2". The gun shoots the 165�s almost a well to 200 (I can't find the setting now) but the 7mm is my beanfield gun so I want to shoot the load that shoots best at 300+. Overkilled is still dead so I hunt whitetail with the 175�s. The gun is so accurate I still don�t shoot up anything we could eat. I�ve made seven perfect chest shots and an ugly head shot at 345 yrd.s.
I tried various bullet wt.s with the .270. It�s shot several well (140, 150) but it shoots inexpensive Rem. 130 gr. Core-lokt best. A setting of 1.9 yields one ragged hole at 100 yrd.s. The Core-lokt bullets have worked well on whitetail so I can�t see a reason to hunt with anything else. Love my .270!
A couple of other things I�ve learned the hard way about trying BOSS settings at the range. Date, label and save all targets! Record the results of your experiments in a table and keep it in more than one place. I�ve lost the results of some expensive range time to a computer error, and when I pulled out my old targets to back into the data I discovered I couldn�t remember as much as I thought would. Little groups of 7mm08, 7mm Mag and .270 holes all look alike and if unlabled won�t tell you squat in a year.
Maybe because it is stainless. As far as the sweet spot goes, Trial and Error is the order of the day for your handloads. After all, whatever group you are getting could be better if you moved it just one more notch, right? 
