As I am also not familiar with your machine, I would suggest to follow what the manufacturer's recommends at least as a base point/start point as to lubing and the assembly. Sometimes that leads to the fact that the recommended product or part is not to be found. Oil comes in a "very large spectrum of types", the same to be said for grease, and sometimes parts, and paper works.
There are crossovers covering many different oils and greases, however not all, sometimes you can not even get the product in Canada, ( not going into that!,,#£¥).
As to bearing placement/assembly in a piece of a equipment, understanding what is happening is important and "not alway" apparent. Is the bearing allowing the shaft to turn while being supported and kept in position and or alinement, is the bearing preloaded on the shaft or in the housing? Does the bearing have both races the same width?( many are the same width, but some are not). Spacers used to take up space and or to preload, or to allow preloading with a threaded cap/nut in many cases.
As to the bearings, 7205 replaced by 6205 sealed, they are very different, the 6205 is a "plain" ball bearing, the 7205 is an angular contact bearing. It seems the 7205 bearings may have been replaced with the 6205 bearings possibly due to price/availability, very/most likely after production. They are not up to the same work loads or thrust loads as the 7205 bearing. I would replace them back to the 7205 bearing, in doing so some other parts, shims, spacers may need to be replaced that seem to be missing, all while trying to see if anything may have been "modified ", I am not not trying to put you off on this, just saying.
Remember, it is a BridgePort head, many have walked this road ahead of you, the people that rebuild these for a living know more about these then I do, and they likely warranty their work.
And as usual this is my views, thoughts and may not be the same as others.
. I put it vertically and used car bottle jack with help of random parts scattered around.
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