Need Help!- Two stroke c/i liner material

[Bob Monkhouse]

I would like advice from anyone as to suitable Cast Iron for lining two stroke motorcycle engines. I have used Spheroidal Graphite(S/G)Iron in the past although its been quite a while since I linered a barrel. I have been told that it can be too soft for extended use but is this because it may need heat treatment before machining? I understand that S/G is formed using grey iron but introducing manganese at the beginning of the process and then magnesium at the end to condense the grain structure, Is this correct?
Is there a more suitable iron for this purpose? S/g seems an ideal material because of the large grains of graphite in the structure and also the voids between the grains to aid with the limited lubrication of the two stroke engine.
Any and all advice would be welcome, my thanks for your time, Bob Monkhouse.