Those symptoms are exactly like mine.
I tried the BG gloves and they worked for a while, but I think I may have squeezed too hard and the pads in the gloves moved apart and became less effective.
I tried swept-back bars (Humpert "Trackers") and they helped:-
http://www.fozzie.org.uk/bike02/06.jpg
http://www.fozzie.org.uk/bike02
But the best solution for me was the Nitto 'Tache' bars:-
http://www.fozzie.org.uk/bike01/02.jpg
http://www.fozzie.org.uk/bike01
I can ride or hours without numbness now (it's my knees that give up).
I use a Brompton in my lunchbreak, it has straight bars and I still get the numbness after less than an hour.