Would not advise trying to hone Nikisil cylinders..............
unless you have the proper hone, and experience. It can and is done, both for your purpose and to fit skirt clearance on new pistons after cylinder wall is re-done, but requires a special diamond hone and knowledge of how to use it. Sunnen makes the one I am familiar with, there may be more. Based on personal experience, use a ball or non-diamond hone at your own risk!!
Call "Don" at 225-293-9851. He has these special hones, much experience using them on Nikisil, and also can sleeve Nikisil blocks. He has done MANY Merc V-6 blocks over the last 10-15 years. He built engines (and still does) for a National and World Champ PRO (alky) racing teams.
There are others that do this work also. If Don can't help you PM me and I will give you some more names.