Tripod advice - please

I currently have my Wimberley WH-101 mounted on a Bogen 3021 tripod and carrying a Sigma 120-300mm f/2.8 (about 6 lbs) plus Nikon D70 and SB-800 flash. I have just purchased a Nikkor 400mm f/2.8 AF-I which weighs in at about 14 lbs. I also have the opportunity to trade into an older (but in good condition) Gitzo Studex Performance tripod. The owner has not priced it yet and I am wondering:

1. About what it is worth in good used condition with some scuffs and such?

2. Is it substantially better than my Bogen 3021 for my new application?

Any advice appreciated...

What specific Gitzo model is it?

Guy

He said he thought it was a 320 when he bought it. I think today's equivalent is the 1320 but I'm not up to speed on Gitzos.

Here's some info you can use to compare with the 3021:

GITZO 320 SPECIFICATIONS

Column type: Rapid
Lowest Height: 19.5 inches
Max. Height: 76 inches (w/ column extended), 62 (w/ column down)
Closed length: 29 inches
Max. Load: 22 pounds
Leg Sections: 3
Leg Spread Angles: 3
Weight: 7.5 pounds

Guy

If it is the 320, then yes, it is substantially better than the 3021. At least I think so. It's taller, heavier, sturdier. I have both the 3221 (black version of 3021) and the 320 and I prefer the 320.
As far as what it's worth, you got me. A new 1320 is around $350. If the 320 is in good shape and only minor scuffs, maybe $250-300?? Just a guess.

The new lens by itself is close to the manufacturer's recommended load limit of 15.4 lbs. I would go ahead and trade for the Gitzo as I believe it will make a much more stable support for your big glass than the Bogen will. I have a 3021 with a Kirk BH1 head and Wimberly Sidekick, and a Gitzo 1348 with a Wimberley WH200 II head. I find the Bogen setup to be marginal with my Canon EF 300 f/2.8 L IS and a pro body, and impossible with my EF 500 f/4 L IS. The Gitzo, on the other hand, is solid as a rock.