337DC Trizact belts in grade A100 and size 675mm x 40mm are the best products for creating a consistent satin grain finish over many metres of stainless steel handrail.
Use the Trizact A100 belts size 675 x 40 on the Cibo Finitube tube polisher (search: SMFT) to blend to a 280 / 320 grit grain finish.
Always finish using a light touch action with a very fine surface conditioning belt ( search: VT RC3) after using the Trizact A100 belt.