Boots Pressure Barrel for souring?

Hi all, I won a 30 year old Boots Pressure Barrel in a raffle last year and had been wondering what to do with it. What I've come up with is using it as a vessel for souring beers/aging on fruit. I have no interest in serving from this barrel, but and curious if anyone has used a Pressure Barrel (equipped with airlock, of course!) for souring? It is made from a plastic which has me wondering about oxygen transfer through the material. I'm ok with a little bit of oxygen transfer, as that would occur if I had a wooden barrel, right? I just don't want the extent of the transfer to be as high as that of a plastic bucket.

Thanks!

Well, with all the insight provided P) I'm going to just go for it. I've grown a 2L starter of WLP645 for a week and am ready for my trial run. I did a 10gallon split batch of saison using WLP585 and Danstar Belle Saison. I'm going to put 2 gallons of each in this Pressure Barrel with 0.5-1oz of oak cubes and the decanted starter of my Brett Claussenii. I figure leaving it be for about 6 months will give me the Brett character I'm looking for. What do you all think?

sounds like a plan!

i would fill it pretty full, like up to the neck, to limit how much O2 the beer is exposed to, and how much air gets sealed in there (which might contain acetobacter).

what's the total volume of this thing, 4 gallons? i'm wondering if an ounce of oak for 6 months might be a bit much.

The total volume is actually over 6.5gallons. I didn't want to do the full thing as I still want to keep most of the 10 gallons unbugged. I'll definitely be purging it with CO2 prior to racking to keep any acetobacter infection minimized. I was actually initially going to use 2oz of oak cubes, but someone else commented on that might be too much as well. I'll probably just do about half an ounce. I thought it would add a nice dimension and also give the brett something to chew on.