Schaefer Line Controlled Genoa Cars

[Shorty]

New to me Sabre 362 has a set of Schaefer line controlled genoa lead cars. I had this rig, except Garhauer, on my Pearson and loved them. Schaefer has plastic sleeves that run on the Tee Track. Garhauer has torlon BB's. I could pull the Garhauers forward under load up to about 10 kts breeze.
Experience with these? Will they adjust under load?
Previous owner actually removed them and replaced with the standard crawl-forward-and-adjust-when-on-windward-side. I think he wanted to reduce line clutter on deck.
The Garhauers are the bee's knees but the Schaefers are in hand.