All the iron sleeved cylinders I've seen have small port area's that need correcting along with the timing changes if doing so, the head has to be re machined to bring the squish band out to the 49mm dia so 1mm wider all around with the same angle.
Clearances and rig gaps with the Chinese parts is a gamble at best, if you want to build a better performing longer lasting engine there are better options and things you can do to achieve this, Like ceramic coated cylinders (same process as nikasil) Mz has some g4 versions or Falcon 911 has a dio reed or piston port version's and these with a properly fitted piston and and a single ring or two 1mm thick ones instead of 2 2mm thick junk rings make a huge difference in wearing/braking in properly and then sealing better for longer life and better performance. Do your research there is alot of info on the site about the steel/iron sleeved jugs, Ill give you a heads up they are not done right by any means shape or form, most crucial to me is the bores are not straight when checked with micrometer along with being ill fitted and needing alot of work not worth the effort to me.