Re: caulking sideboards
i prefere poly butyl caulking as well for exterior application. ive seen silicone fail more times than poly,
the 3 types i use are "Flex 9000", "Flextra" both by mulco and then "Quad" by lepage.
some people swear by "MONO" however water breaks it down which rendors it useless
as for application and the correct conditions, as mentioned dont apply it in direct sunlight as it will skin over too quick to tool if needed, and dont apply it when the surface is wet from either cleaning the residue of old caulking off or just after it rained. it wont stick correclty
fire up the saw and make some dust