That's great TD...
Yes, the 5 gain is good for various phones. Give the 10 a shot with the Beyers and then see if the 'Sones cooperate.
I saw that you checked out the LD tube rolling thread...Those guys over there are real players...lol...I remember when the EF91, 92 and 95 family as well as all their variants was going strong. Now with all the other tubes they have found and cutting pins and strapping, they have taken it to a whole 'nother level.
I'll give the 10 a try this weekend, yeah the guys in the tube rolling thread are some serious hard core rollers.
Gonna be fun playing with some heptodes down the road.