I load MBC smallball bullets over bullseye powder and have had very good accuracy out of them. Haven't had much leading and clean-up normally takes about the same amount of time as I spent when shooting jacketed bullets. The only two guns I have shot my load out of are a Ruger SR-9 and a Springfield XD-M, so I can't say anything for the sigmas for sure but I would say your experience would be similar.

To answer your questions:

1. Yes it is normal to load a .356 lead bullet in 9mm, lead bullets are always about one thousandth over the jacket bullet you would use in order to get a good bullet to barrel seal.

2. The lube is already on MBC bullets, most hardcast bullets come already lube the only time you have to lube lead bullets is if you buy them unlubed or you are casting your own.

Also if you are thinking about plated bullets I would just go with FMJ in 9mm the cost difference is VERY small. I have used some FMJ bullets from Roze Distributing and they were very accurate and the price isn't much different than plated or lead so you may want to check that out.

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Drew