Once the mast is up I'd start by slacking all the shrouds and the backstay and adjust the forestay turnbuckle to get about 6 inches of rake (hang a wrench from the main halyard and measure from the back of the mast at the step). Then, as Benny suggested, I'd use the Loos gauge to set the upper shrouds and forestay to about 15% of the wire breaking strength. After that, set the lowers and the backstay to about 10%.
Now, take the boat out with full main and your usual headsail in about 10-15 kt of wind (close to when you'd normally reef the main). These are probably the conditions that place the highest load on your rig. Sail close-hauled and look at the leeward shrouds; there should be no slack. Come about onto the opposite tack and check the opposite side. If both sides are not slack, you're good to go. If not, tighten the loose shroud(s) one full turn and resume sailing closehauled. Repeat the process until the leeward shrouds are just tight on both tacks. There's no need to tighten any more, it just puts more load on the chainplates and the mast step.
Now, measure the tensions with the Loos gauge and note them in your log book along with the sail sizes and wind and wave conditions for future reference if you ever have to set the rig up again.
In case you're wondering, the forestay should be straight or sag slightly to leeward when closehauled under those conditions. When you raise the jib, you can use the jib halyard to fine-tune the tension in the luff (it effectively becomes the forestay) for the prevailing wind on any given day (more for windy days, less for light air days). If I remember correctly, the H22 has a winch on the mast for that purpose. The backstay should be set so it's not slack when sailing closehauled.
Rig tensions should be set for your boat, your sails and the wind conditions in which you typically sail, which is why the final tuning should be done on the water. It's a little more involved but will pay off in terms of reduced load on the rig and chainplates. Good luck.
