Trad bend bar have longer reach compared to more compact bar like the SL70 so it make sense to run a longer stem to compensate for the shorter reach.
I received the Vision track crankset, it comes with single length chainring bolt but they require a T30 torx key (a 4mm allen key can work but be careful) and the nut is the spinny type. Good thing I already planned the dura-ce chainring knurled bolts.