I used a bit of 3mm walled tube for mine .... May be completely barking up the wrong tree !!?? ... But If you are only puting a radius on the outside edge, you'll only need material thicker than 2.5mm ??
You could also choose a size of tube that you can get a plastic end cap for
Bop that in there .... that should take care of any radius issues
That said .... I havn't been through the IVA ...... Yet
