Depends on your style of playing....but can only assume you are not going for super speedy playing? I've tried Spiros on the bottom...however the contrast from steel to gut is severe. Recently put an Innovation Golden Slap E on and works well with gut (The Innovation Slap series are very very close to gut in feel and sound). The Innovation E has way more control than the gut E with more definition and punch than Gut, but without steel harshness. And Tuning is stable! Working so well I may even swap the A over also. Interested to hear what you other perhaps more experienced players have discovered...?