About how long is a port, sherry, etc finished?

[classyndry]

I received a spirits aging barrel as present a while back. I tried some rum finished scotch a while back, and since I had a bunch of rum on hand, I decided I'd try to put a rum finish on a scotch myself. I already have some rum aging in the barrel. Since its a small volume barrel with a lot more surface area than that much rum/scotch would normally see, I'm planning on pulling the rum out in about a month, which would give the rum enough time to seep into the wood and add to the scotch finish. Then I want to put some scotch in, but I don't know how long to shoot for. Right now I'm thinking about starting with something fairly basic, but I've also considered using something a little more intense in flavor. So maybe a Macallan 12 to try to fully taste the rum finish, or maybe like a laphroaig to temper the rum finish with some smoke. What would you guys do? Any idea how long a port, sherry, or rum finish generally takes? I can taste the scotch to evaluate its progress, but since its low volume, each sample means less finished product and more air in the barrel.

Thanks for the advice guys!