getting it right
I take it you want to rake your mast to balance CE and CR. It takes me about an hour to do and once done is set until I need to de-rig. With the boat sitting on its lines in the water,loosen off the sidestays so they are loose but not sloppy. Loosen off the headstay. Then tie the winchhandle to the main halyard and use it as a plumb-bob. Set the forestay and backstay to tense but not taut when the halyard line is 7 inches back from the aft edge of the mast.Now tighten the lower sidestays in pairs, a port and a stbd. Takng your time to bring them in equally, a few turns per side, tighten them until they twang when you pluck them. Then do the masthead sidestay. Check your plumb line halyard to be sure you are still raked 7 inches.Harden up the forestay and backstay equally, little at a time until everything is taut. Now, sight up the forestay, lining up the forestay with the centre of the mast and look for a sideways bend, esp. above the spreaders. If there is one, take it out by tightening the appropriate sidestay. It won't take much unless you got way off when you were doing this.My boat will point very high set up like this under full sail plan, 1 reef in main, and stormsail and reefed main. It may be more balanced than some like, but in high winds, C-22's round up pretty hard, and this helps.I hope this is what you meant. An adjustable backstay is good for tweaking the masthead fore and aft when racing, but really is not needed for a boat set up for cruising.