I have used his 5/6 (called the poacher or stalker) twin line and also his 6/7, they are good quality with very low memory and have invariably worked well on every rod I have tried them with. Really don't understand his twin rating though, no doubt someone will enlighten me! I have also used his Salmon lines and been very happy with those too.
I did manage to get the lines at a very decent price (the 5/6's were seconds due to colour bleed and cost next to nothing so I bought 3

). Currently I am mainly using a Cortland 444 WF5F (Peach) and love it, I know it's 'old hat' but really is a lovely fishing line.
I have just seen this advert...
Snowbee XS WF7F Ivory White these get really good reviews too, might be worth a shot?
Andrew