Hi Christian,
jeg svarer pa engelsk, det er lettere for meg, min norsk er ikke so bra.
I don´t have this NXT-Switch Type in use, but maybe you should have a look onto the
RIO Spey Line Recommendation 2017. (look at page8)
http://cdn-tp2.mozu.com/15440-m1/cms/files/c0865c37-2497-4964-b160-12335f25d4b8
I have a Evotec Cast 5110 in use, the Loop Line recommendation was about 278grain/18gr, that was to light for me.
The RIO Spey Line recommendation is about 300-330 grain (19,4g-21,4g), actual I use it with an InTouch TroutSpey Line #5 with 350 grain (22,7g) and it works for me but I use it with Underhandcasts in tight areas.
The RIO specs give a good orientation for example the RIO Scandi short #7 has 425 grain (27,5g)
Haper det hjelper.
Jörn