Making my own Whisky barrel cubes

I have been planning on filling my own whisky barrel, but just have not been able to get it worked out where my group can get together and do a couple big batches and get one filled. So now I have 2 barrels with a 3rd one on the way this summer. I was considering cutting one of them up to use like cubes or strips in smaller batches.

I was curious if anyone had any experience doing this and if it would be better to cut big strips or into cubes?

Would there be a concern with what would be the beer contacting the outside portion of the cubes? If these barrels have been toasted and or used then the flavor you would want would come from the inside of the barrel. By cutting it into cubes you would now have the beer absorbing flavors from the outside of the barrel as well.

Ya I figured I cut either cut or sand off some of the outer layer then soak them in the bourbon that came out of them to sanitize them.