Roll issues during high-altitude staging

[phoenix_ca]

If that's an issue, you can set-up MJ's ascent profile to start the gravity turn later, preferably sometime after the really heavy bottom stages are gone (boosters are a good thing to wait to burn-out before turning; dropping radially mounted boosters whilst turning can be...problematic...).

[EndlessWaves]

Would those tanks cause roll issues if they are swaying back and forth around the long axis of the rocket? I remember watching those tanks rocking and rolling during roll oscillations during the first part of the ascent. That's why I added an additional 4 struts to the posted craft.

Yup, just had a look at the craft and it's the stacks of tanks wobbling sideways that are causing it. You did add braces but they were at almost right angles to the movement so they had little effect. You want to attach the braces between the tanks in a stage so they form rings around the ship. Even just two sets of braces around the top of the stacks will cut down the wobble enough to let SAS handle it alone (without winglets). For total stability you'd need to brace the stacks just above the engines as well, although I'd personally move the decouplers down instead.

Think of struts as steel bars rather than glue or shock absorbers and you should have a better feel for how to place them - they'll both push and pull and are much easier to rotate about their attachment then they are to stretch or compress.

[cardgame]

Struts have stopped all of my launch stages from rolling. One on top, one on bottom.