What are your opinions about the quantity, the toast, and how long the staves should be used?
I agree with Craig (
@cmason1957) that advising is tough, as your tastes are unknown to me and probably different from mine. I like oak as an accent, not a primary flavor. And the amount of oak a given varietal can handle differs greatly.
Medium toast will impart nuttier, heavier flavors than the light toast, which is fruitier/sweeter flavors. Changing the toast is a significant change in the flavor profile.
I suggest you pull one of the staves from each carboy, wrap them in plastic, and put in the freezer. You need to see what differences a single medium stave does to each wine. Taste each wine every 3 to 4 weeks, recording your impressions. After each tasting, read the previous records from first to last, so you can see how the wines changed. After 3 to 5 months, if you believe a wine needs more oak, replace the stave in the wine with one from the freezer.
My experience with Syrah says it can handle a lot of oak. I have no experience with Barbera so I bow to Craig's experience on that one.
I have a spiral to put in my wild grape carboy and I’ve been thinking
. Will it float or sink? How do I get it out when I think it’s had enough?
As Fred (
@mainshipfred) said, the oak will sink. The answer is to use the racking cane as a straw to draw the wine off the oak. Keep in mind that you may pass out from lightheadedness before you get drunk, as it takes a lot of suction to get the wine out.
In a more serious vein, I tend to use cubes, and racking is the answer. I go lighter on oak and let it set longer, so it may be in the carboy/ barrel for 5 to 10 months.
I agree that oak adjuncts give up most of their flavoring in 3 months or so, but I've experienced subtle changes through 6 months. However, I can't be positive if the oak is continuing to flavor the wine, or if the natural aging of the wine is altering the flavoring imparted by the oak, or both.