I wouldn't waste my time with the Carbelite. B&C makes a decent $250 stock in the Medalist, but I don't think they make one for pre-64's. In fact there are no budget priced pre-64 stocks out there other than the Carbelite that I know of.
If it were my rifle and I liked it, I'd spring for the McMillan. Yes, they are pricy, but are well worth it.
The next best option is to spend some time on Gun broker, E-bay etc. looking for a used pre-64 stock. There are a lot of other guys who have spent the $600 for a McMillan and will sell the old stock for $150-$200 in order to recoup some of the money. They are out there if you look. It may take a few months until a decent one turns up at a fair price.
You may also find a used McMillan. I have 5 rifles in McMillan stocks, all were purchased used or off McMillans Specials page for around $450 instead of $600.
On McMillans website they have some stock specials. When ordering most people pay a deposit, then pay off the stock when it is finished. Sometimes people don't purchase the stock after it is built. McMillan sells them for what is owed against them. If you check their website regularly you'll sometimes find deals, but you have to move fast to get them.