There are risks with very light loads of smokeless, but it tends to be more of an issue with slower powders. I would not out 4198 in that category, but it also seems an unnecessary risk. 

With the greatest of resoect, 'testing the strength' of an unknown gun with light loads of smokeless powder is not a good idea. If it is suspect, it needs to go to a gunsmith with the metallurgy experience to make a determination on safety.

As to lighter recoil plinking, a collar button bullet, like the Lyman 457130 150 grs is going to be the ticket. While I would counsel 35-40grs of 2F black powder and fiber wads to base for soft shooting, if you want to stick with smokeless, IMR 4227 and IMR4198 will both offer light recoil loads. Here is the bullet and load data:

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Alternatively, this is where Trail Boss seems to do well, another light bullet and TB loaded to just shy of the bullet base, though that is not particularly economical.