To gauge the size of the spacer just......
Stick the spacer tube between the bearings/cups (use your spindle to make things easier) and hold it against your bottom bracket. How much space is there left over?
Cranks dont work well when the bearings are pressed against the spacer and crushed (when the spacer+Bearings+cups is less the the width of the bottom bracket). At the minimum the spacer+bearings+cups should be the same width as the bottom bracket.
Profile cranks like the spacer+bearing+cups to be a couple of mm bigger than the width of the bottom bracket with the drive side cup firmly pressed against the Bottom bracket and the non drive side to be a couple of mm slack against the bottom bracket. This is because the crank arms are tightened against the bearings and spacers and it avoids crushing because they are tightened aginst each other.
Redline cranks (I think) dont need any slack in the setup. They have crank spindle bolts and two side bolts so that the cranks can't loosen.
My cranks came with 2 spacers (or maybe I nicked one from another crankset). I think the blue one is for a different size bottom bracket. Maybe you need the spacer from other one (Mid,US, Euro, Spanish)
How much slack have you got?