I've converted several glow engines to ignition, even run one (Saito 1.50) on gas. In general, larger engines can run less oil, glow fuel or gas. Also, with spark ignition engines running methanol perform well on less nitro content than they need on glow ignition.

My experience with YS engines told me that they transitioned better on higher nitro content but with ignition this is usually not so critical. So why the high nitro content? There's certainly not any saving on fuel cost.

CR