Do you think it would be ok to just leave it in the barrel and bottle up as I go along? That way I can test on a regular basis 
and decant as bottles become available. I'm going to reuse screwtops but also have some plastic corks which I might try.
Air is death to wine. Leave a bottle that has been opened and it will turn bad in 6 days. So its not really possible to put wine into a barrel and decant it as you go.
Siphon it from the fermantation container into a barrel by all means. Thats a good way to get the wine of the old must. But realistically you should bottle it up straight away. The only way to keep it in the barrel would be to ensure CO2 is protecting it. What I do is siphon from the fermentation bucket to a PED 5 gall bottle. I cork it, it will have a small head space. This will fill with CO2 and I can leave the wine for a few more days. The next time I open it I bottle it, all of it. If theres not enough for a last bottle then I drink that bit.
The problem with your barrel is, I think the head space above the wine will be quite large. If you seal the barrel then the wine will be ok for a few weeks. But when you open the barrel you will need to bottle the entire amount.
In your kit they mentioned 6L bladders. Now this is very different. If you fill a bladder it will be like a wine box. As you decant it the bladder will colapse. No oxygen and so the wine will keep. How long does an open wine box last? (Ive never kept one more that a week :blink: to find out.
So you could go from the barrel to the bladders. Then bottle some for deep archive. Drink the bladders withing a few months, say two weeks after opening. Or bottle from the bladders.
Im going to buy some of those bladders as it seems like a good idea.
