Roof venting on house with no eaves

I have a house built in about 1942 which has a problem with ventilation. The roof has only one rooftop vent about 8" x 8" and no intake vents at the lower part of the roof.
There is no eave at all and Ice dams have always been a problem. I will be getting the roof re-shingled as soon as weather permits.
I am somewhat convinced to use smart vent at the lower end of the roof and ridge vent ll at the top. Is this a wise choice in sometime severely cold weather and snow?
I have also considered the in-vent and the edge vent but, I seem to be drawn back to smart vent. In-vent shows installation about 36" up the roof which makes me wonder why? I think it should start as low as possible.
All help on this topic will be appreciated. Thanks.