If you follow the normal speed schedules, if I remember the dash 8 correctly 160 til somewhere around 20,000 feet and then decrease it gradually until you level off you can't go wrong. Adjusting this speed for whatever case will not make "much" difference. A minute or two does not make a difference in the whole scheme of things.
On jets we climb at a speed somewhere around 300 kts and transition to somewhere around Mach .80 which is close if not exacty the cruise speed. These speeds are automatically adjusted for by the flight management system which takes into account the price of fuel, weight of aircraft, and wind.
By the way there is no "step" for speed or altitude on an airplane, that is unless you are flying floats.
As for which mode to use (v/s, ias etc) it is best to use ias for climb. Never use v/s unless you watch it like a hawk. In some windshear conditions it is possible to overspeed or even stall when using v/s in a climb. In really severe bumps try to hold your attitude to carry out the task (climb descent level)
crazy.