RE: 06 SSR 4.6 What mast??
400 Blue Line will fit nicely if your mast base goes to zero, or more precisely 2-3cm, because the rigged luff (mast tip to mast base pulley) length will be around 403cm. Bend curve and stiffness from the BlueLine will be OK. Use a fair amount of downhaul. We're currently testing that mast as the reference in the new CodeRED 4.6/5.1/5.6m.
Cheers ~ Ian