Hi
Your right dead slow retrieve this time of year i fish once a week through the winter mostly use a floating line 15ft-18ft home tied tapered leader and weighted nymphs very slow fig8 ............reckon ive only lost two on the bottom since october

I can feel my nymphs bumping through the weeds so i know its fishing in the right place but a very very few hang ups
If i feel i must use a sinking line with a slow retrieve then a boobie holds its self up , or a muddler can be used in its place.
Personally i find a floating line and long leader gives me more control i can fish my flys/nymphs deep and slow in winter ...."SLOW" being the key in winter.
Ive always find sinking lines and "non floaty" patterns fished dead slow results in lost flys lots of lost flys

also less fish

as you are forced to retrieve at a faster pace then the fish want in cold conditions