I'm in the process of turning my contender into a carbine, and I see that there are a few different ways to hook the forearm onto the barrel. Bullberry and Virgin Valley both have their own way of doing it that's different from the T/C method. I'm going to be shooting .223 out to about 350-400 yards, mostly at gophers (ground squirrels), and I'd like to eliminate whatever variables I can. What should I be looking for? What should I avoid? My barrel has the standard profile and attachments.

Any info will be greatly appreciated!

Go with either the hanger bar system or a forend that is truly pillar bedded. In addition to VVCG and Bullberry, Dave Van Horn can accommodate your forend specifics as well.

Then add a Bellm oversized hinge pin, and you're all set to wring the most accuracy out of your rig.

If you decide to pillar bed. Here's a technique that worked well for my Encore rifle.

http://www.serveroptions.com/ubb/ultimatebb.php?ubb=get_topic;f=35;t=001374#000000

Methods I've tried include:
Standard forend with wood touching all the way.
Standard forend with felt glued to forend between screws. (freefloating the rest)
Standard forend with steel washers placed on the screws to freefloat the barrel.
True pillar bedded forend.
VVCG/Bullberry forend.

I prefer the VVCG bars/forend for my barrels. I feel it is the best system. With some barrels, I have found that the hanger bar didn't help any in the accuracy, but I have never had a barrel shoot worse using the bars instead of another method.