To determine which size of track you need, Seldén has developed a Main Sheet Track Calculator which is available on-line. You will be asked to fill in your boats Righting moment at 30° heel - no worries - there is a calculator for that too. 

https://support.seldenmast.com/en/services/calculators.html

The System 22 Main Sheet Track Assembly is designed for medium-sized sailboats, with a 6:1 purchase operated through cam cleats on the car. The kit includes:

• Main sheet car 442-149-02 with integrated cam cleats for the control line. Top-guides and fair leads enable operation remote from the car as they guide the line straight in to the cam cleats. With a continuous control line you can operate the leeward cleat and the windward cleat from the windward rail. The car is black anodised, extruded aluminium and runs on Torlon® ball bearings. It features plain bearing polymer sheaves for control lines and an AISI 316 mirror finished stainless toggle for Seldén PBB 50, BBB60, R60 and A60 blocks. The toggle and sheet block are supported by a rubber stand-up collar to improve function and to dampen vibrations. 
• End controls 442-112-01. Plain bearing sheaves and an integrated becket for the control line. Rubber shock absorbers prevent damages on car and end controls. 
• 22 mm hard anodized standard track for M5 screws. Hole distance is c-c 100 mm. Length 1500 mm.
• 12 m control line, 24-plait Polyester.
   

Length: 1500 mm
Max MSL: 20.00 kNm