Thinking it through; if you put the EBB so the BB axle is at 9 o’clock (I’m always assuming you’re looking at it from the drive side, ie, 9oc is as far towards the rear as it’ll go)
Fix the chain using the minimum # links to get it around both chainring and cog and still connected.
And then rotate the EBB so the axle moves anticlockwise (9->8->7->6, etc.); the chain slack must get taken up because the distance between wheel axle and BB axle is increasing. Making allowances that the top and bottom chain run isn’t exactly parallel, but for these purposes it’s close enough….. to take up the slack of one pair of links (inner and outer = 1″) then a 1/2″ change in axle-axle length takes up a pair of links of slack – 1/2″ each from top and bottom.
If an EBB doesn’t have > 1/2″ of adjustment I’ll eat my hat. And if you need more adjustment than that, then you didn’t use the minimum # of links in step 1.
However:
Just re-reading one of your earlier posts.
I’ve never used a half link and hadn’t reckoned on needing a ‘magic gear’ to run the EBB @ 5/6 o’clock – tips appreciated !
You don’t get to choose where the BB axle will be. You decide whether to rotate it down for a lower BB height, or up for more clearance, but how far to rotate will be decided by a combo of chainstay length, the ratio you’re running and how stretched the chain is.