If you want high speed with small grain and plenty of contrast, I would strongly suggest you try TMY2 (Tmax 400). In Xtol it works nicely out to about EI1600 with contrast that can be tamed and with Rodinal you can get EI800 from it without any particular effort. The grain is far, far smaller than with HP5, even using Rodinal. I wouldn't hesitate to make a 24x30" print from 6x7, i.e. 11x16" from 35mm; it will have visible but subtle grain at that point.
I have several 16x20" prints (from 6x7 TMY2, so that's slightly less enlargement than an 8x12" from 35mm) which are nearly grain-free. One at EI400 (normal contrast, though the lighting is contrasty) and one at about EI3200 (extremely dim flat lighting just after sunset on a day with full overcast, developed for EI1600 and printed at high contrast for a noirish look).
And you don't need much more (IMHO) than 1/125 for street shooting. If I can shoot street at 1/125 with a 6x7 SLR (usually 110/2.8 lens), you're doing something grossly wrong if you can't get sharp shots with a Leica at that speed. I only shoot 1/250 if I'm using my 250APO.