Kent-I have the same issue with my 5/8" Thompson Lyle Jameison gouge. I loved it when I first got it a few years ago with its original grind; it was my 1st big gouge and helped me learn all the basic cuts very well. It was and is advertised as being parabolic, but the wings have slightly less recurve compared alongside my Crown PM Ellsworth gouges. I vaguely recall some debate about whether that grind was/is truly parabolic. Anyway, for reasons I still haven't figured out, I have been unable to recreate the Jameison grind with either an Ellsworth jig or the Vari-Grind to my satisfaction (and my freehand grinding skills are definitely a work in progress!), so I find myself reaching for it less and less, which is a shame because it's an expensive, well-made tool that I would like to put back in the rotation. I should probably just contact Lyle himself.
That said, I have been looking into a larger BOB gouge, though 5/8" seems like a big gouge for finishing cuts around to the bottom, at least at my current skill level. My current D-Way BOB gouge is 3/8" IIRC, which is controllable when I'm doing everything right. I'm still refining those final light sweeping passes, and finding that the fundamentals (a freshly-sharpened edge, gouge locked against my side, pressure down on the tool rest, watching the nose/wing position while observing the horizon, and letting the tool feed into the cut without pushing) are making a huge difference. If I overcome my inertia to reach out to Lyle, I'll try what he suggests. But I am intrigued by the concept of it as a bottom feeder, so I may just try that. I often start a reprofile on my tools with a 50-grit belt on my 2x72" grinder before refining it on the wheels, so it shouldn't be too hard.