Addressing gap between fieldstone foundation and rim beam (built 1900) – GreenBuildingAdvisor

I discovered several gaps between my fieldstone foundation and ridge beam (home built ~1900 in MA). 

My inclination is to pack with non-shrink grout for more beam support and stopping the air, but I don’t know 

1) if temps are appropriate right now, and 

2) if i’m going to cause another issue due to direct contact with the beam. 

Also, many of the gaps would be way too small for me to pack in… could I use something like a R Guard joint and seam filler from Prosoco or Zip Liquid Flash? 

MassSave did air sealing and insulation last year. I found these gaps while investigating why my basement was still so cold this year. 

I’m open to a two step process that includes a current stop gap for the air leakage (stuffing with mineral wool??), and then addressing the problem more permanently when it’s warmer out.

Thanks for your input!