Lots os testing to come, not enough shaving days!
According to Gillette.Try with the safety bar firmly against your skin and rotate the handle until the blade starts to cut. Rotate small amounts in the same direction until that tugginess goes away while keeping skin comfort as your main priority. If the tugging doesnt stop, try a different blade. I believe blades to be the most personal aspect of the entire equation.
Agree. For me the ATG is always the very last pass after reducing as much growth as possible, whether thats a WTG and ATG and done shave, or a WTG, XTG and ATG 3 pass shave. I won’t even attempt against the grain for a first pass unless it’s a touch up shave with a mild razor. Trying to do so has always ended In poor results, discomfort, irritation, nicks, cuts…not good for me.The angle is the angle based on my experience with any razor. Very little adjustment to use a razor most efficiently. I had an issue for some time with the DE89 but a couple months ago, @Alum Ladd made a suggestion to me regarding angle. I was so used to shaving with all my vintage Gillettes the same way that the tiniest adjustment with the DE89 solved my issue with that. I don't understand the "riding the bar", "riding the cap" method. There is an optimum angle for each razor. Past that, it seems to be about light pressure and a good blade. I shave all three directions with multiple passes with any of my 10-11 vintage Gillettes with zero issues.
One guess is you might not have reduced your whiskers enough before you start your ATG pass. By that point, the reduction should be at the point to make an ATG pass easy.