Bed the action and float the barrel and see how you like it before taking other steps. You do not really need the aluminum pillars in a well bedded synthetic stock, but it does help some.
It is possible to stiffen the fore end if it does touch the barrel when you use bags or a bipod but first I would see if it actually does flex enough to be a problem. Do not be too cute when floating the tip of the fore end. Leave a reasonable gap that will allow more than one business card to slide between the barrel and the tip of the stock.
If you ever want to upgrade your 700 there are some really good aftermarket stocks available. Poke around Stocky's Stocks web site for a few ideas. Stocks like the Bell & Carlson Medalist are a big upgrade from the SPS factory stock and are not all that expensive.
For the bedding job I would use Devcon or Accuglass Gel from Brownell's. If you do decide to stiffen the fore end the advice that Nomercy has given you is the best way to accomplish it.