I don't think you are going to notice a difference between 853 and other high end tubing that is in production now in terms of ride quality. Maybe a discernible difference between standard diameter and oversize/double oversize though. I think modern steel is plenty stiff and light. High end steel frame these days are lighter than middle of the road carbon frames. If you want a featherweight bike then frame material is almost moot, its all in the wheels/components. The biggest factor in ride feel between your old 853 and a new custom steel frame is going to be geometry. A new steel frame will feel like your Lemond 853 if it has the same geometry. That being said, if this is an early late 90s early 2000s Lemond you are talking about they had pretty funky geometry (slack seat angle combined with steep head angle.) If there is something you don't like about it then I am sure you can get a custom frame you will be much better but it will not be because of different tubing.