Bedding in new davits

[nigel1]

Just had new davits fabricated and will be fitting them to the boat soon.
The foot of the davit is a 5 inch diameter flange which will fit to the swim platform, and there are two other attachment flanges to bolt through the transom.
The base flange will sit on a slightly curved section of the swim platform, and I''m looking for some recommendations for a bedding material to go between the flange and the GRP of the platform so that the weight of the davit can be evenly distributed. Hopefully something that can be squeezed out of tube and will remain pliable for a few hours before setting solid.

Thoughts and suggestions as always will be appreciated