Roper, here's my sense of the market. I know a lot about a few makers.
Hang round the Classic Fly rod forum and use the search bar to query about rod makers. Lots of info there.
Used Grangers and Phillipson bamboo. Plenty available for $300-700. I have 4 grangers and 5 phillipsons from 7'6" to 9'6"and there's not a bad one in the bunch. The 8'6" phillipson and granger 8642 are a joy. Avoid the Granger Champion sliding ring reel seats because they sometimes come undone. Everything else is good. I wrote an article about my Grangers and Phillipsons for Wading List.
When I think of Bamboo fly rods I think of Denver, Colorado. I fly fish the northwest United States. Big rivers and windy lakes with Denver Bamboo Fly Rods.
www.thewadinglist.com
Used Winston bamboo. Hollow build so they feel lighter in hand. Casting machines. Expect to pay $1,000-2,500. Winston still services its bamboo rods which is great in case you ever break a tip. A 9' 4 7/8's winston was best of breed at our PNW fly fishing cast-around a couple years ago. I loved it so much I went out and bought one. You can buy new from Winston if you want but it will cost you $2,500-3,000.
Sharpes of Aberdeen used bamboo.. The Sharpes 88 is a versatile rod. 8'8" 5/6 weight. Most people in the US don't know anything about it because it was made in Scotland. Impregnated so bomb-proof. A Sharpes 88 will cost $250-400. I have 6 sharpes fly rods and think the are perhaps the most underrated rod for our bigger waters. If you find your herters tip heavy you may not like the Sharpes because they have pretty robust tips. The Sharpes 85, however, may change your mind.
I recommend that you cast a bunch of bamboo rods so see what you like. No other way to figure it out. Come over some saturday and Greg Armstong and Para Adams and I will let you cast some rods in the park. You'll learn more from the two of them in 15 minutes than you'll learn from me in a day...
One more thing. If you're buying a rod you want to take on the plane get a three piece configuration. Most of my two piece fly rods are too long to take on the plane without checking. That may limit your winston options or Sharpes options because they mostly built 2 piece.