River anglers often use carbon in preference to glass tips for upstream legering as they spring back harder/faster giving better indication of drop back bites.
I can see the logic Ian if using reasonable size leads,
However to be perfectly honest mate I much prefer to use very light glass tips for my upstream ledgering,
I'll try to explain, sometimes I'll use just literally 2 AAA shot on the line and cast upstream, the lead stays put but the flow of water creates just a little bow in the line and now the mainline from the rod tip to the water surface is now moved from pointing upstream to now pointing directly straight out, there is still a little slack in the line from tip to water.
I actually watch the line and wait for it to move upstream and I then know that a fish is on and I'll strike and normally connect :thumbs:
I'm touch ledgering most of the time and so if I fail to see the line move the line will now easily and effortlessly pull the fine glass tip around and if I fail to see this I by now would of most surely felt it by holding the rod and line
I use all glass tips for all of me river roach, chub and perch fishing as these can easily pick out the the most faintest of taps and bites :thumbs:
I lot of the elderly old school serious roach and chub anglers that I know of would all swear by the use of glass,
I can understand the use of carbon for some situations but for me with my style of fishing and especially touch ledgering it's gotta be glass for all river work.