Hi SouthPaw,
You need the barrel on to get it all straight in the stock, if you do it with another barrel you need to check on a surface plate (or equiv) that the barrel is straight and then assume that the new one will be when installed. Almost all factory barrels are crooked (actions especially) sometimes by a large amount. That is why Rems have the bedding point in the forend of the stock, to force everything to line up and look good, nothing to do with accuracy! .125 will be okay to fill with epoxy. I always make short pillars to extend the holes from the bottom of the bedding block to the bottom of the stock. Leave long (but not through the stock) then countersink or counterbore the front one to what type of screw you are using and mill the rear one when you inlet for your guard so it sits hard on the pillar. Neat way to do it and no escutcheons needed. Make the holes .25 and when finished ream them larger for clearance.
You need the barrel on to get it all straight in the stock, if you do it with another barrel you need to check on a surface plate (or equiv) that the barrel is straight and then assume that the new one will be when installed. Almost all factory barrels are crooked (actions especially) sometimes by a large amount. That is why Rems have the bedding point in the forend of the stock, to force everything to line up and look good, nothing to do with accuracy! .125 will be okay to fill with epoxy. I always make short pillars to extend the holes from the bottom of the bedding block to the bottom of the stock. Leave long (but not through the stock) then countersink or counterbore the front one to what type of screw you are using and mill the rear one when you inlet for your guard so it sits hard on the pillar. Neat way to do it and no escutcheons needed. Make the holes .25 and when finished ream them larger for clearance.