You buy the bearing blue in bearing suppliers, like "ABC Bearings", took me a while to find it and I felt like a dill when I found out where to get it.
I'm going tho leave the nose cap hole as the standard size.
The barrel isn't floated, it bears on the centre line of the forend all the way from the centre band to the tip of the forend, the idea of packing the guards is to hold the barrel down and dampen vibration, don't know the physics I've just seen it on a lot of range rifles, but as it stands I think it will be fine, we'll see. Easy enough to retro fit, but if possible I don't want to add cork, I'm pretty sure they didn't do it on the HT's, correct me if I'm wrong.