Welcome to the forum. Lots of knowledgeable, good people here that are happy to be of help.
To your question...for starters, you'll be money ahead to shop for a good used Modified rifle for sale and you will likely have the huge benefit of seeing the match reports that prove it a winning rifle...or not. The value of that can't be overstated.
Second, while the triple deuce is very good, I'd lean toward a 6BR or 6PPC over it. The 222 has its tongue wagging at 200 and beyond and gets blown around pretty bad.
If you go the build your own route, I'd go the 700 due to better triggers, more and better stock options and better resale, which is not a strong suit for any modified factory actioned rifle, to be honest. That's what makes the used rifle route the best approach, IMHO. You can find them in the $800-$1200 range pretty frequently.
As for the scope, buy the best you can afford but a Weaver t36 is a very good budget scope. From there, the NF BR is a very good and solid scope if weight allows...They are quite heavy at around 34 ounces. The Leupold 40x and 45x comp scopes are decent and March is excellent.
I plan to be at that match and look forward to meeting you. There'll be a lot of fine people there that will be eager to help you get into the game. On that note, I have an XP100 in 6BR that I might part with. It's a competitive rifle and fresh barrel. We can talk about it more then or pm me your contact number and I'll call later. It's a great game and there are lots of matches a short drive away, in this area.
Last but not least, don't just spectate. Bring a gun and at least 100 rounds of ammo...150 would be better. You'll learn more in a day of shooting than a year of watching and talking about it. --Mike Ezell