Lindsey, what happens when you try to lay it off instead of across the line?
When I feel like I'm down the target line at the top I'm still across the line. I tried Softdraw, and if the stars align I end up with a nice high draw. Most of the time I end up underplane with this awful, slappy, unsolid, low hook or push. My stock shot used to be a strong grip drag left fade. From across the line when I try to tumble with a neutral grip I hit alot of pulls. Maybe from coming in steep like you said happens to you from across the line? I don't think I'm good enough for any double moves like that to straighten out. Hell I've been tinkering so much I can't hardly hit anything solid now. Except for the ground with the sole of my club as I smack it down in frustration.
Everything you mention is what I experience.
I hit lots of very good shots when I get the shaft in a left arm matching plane at the top. It's one of those things where I can get it grooving on the practice tee, but it may take years before it will appear on the first tee. Typically i will get the shaft positioned perfectly at the top and then I will have a poor hand path starting down. I have a difficult time controlling both the shaft and hand path when I lay it off. I just think it is an innate reaction I have to feeling the club shaft that open.
If your across the line you still have to control the hand path for "optimal" impact. If you let your hand path go horizontal from the top or even at the bottom, the shaft will suck back under plane.
There have been many great players who have found a way to play across the line. I look at Tom Watson, Zoeller, Carl Petterson all the time and even Nicklaus. They both had the ability to let the shaft back up a bit out of the steep transition then get back on top with tumble. I have almost, but not completely resigned myself to that double move. The other thing is that I am not convinced they (Watson, Zoeller, Petterson and Nicklaus) ever even feel the double move even though, in essence, that is what it is. To them, it probably feels like one move.
I guess in the end, as long as your able to tumble at some point whether continuously from the top or right at the last moment it does not matter.