We have a SailTec adjuster; it replaced an OEM Navtec product that finally needed a second rebuild and I had lost faith in it.
IMO, if you have questions about your SailTec, the company will answer them. Small company with personable folks. Several years ago I called to ask what to do because ours had stopped holding pressure, and they told me not to send it back for a "rebuild" (or spend my money) until I followed their instructions to purge a suspected bit of air. I did so, and it worked without a problem again.
Just for comparison, our masthead rig does not bend much until about 2000#, and so I take it up to 1800 or so on breezy days. Rig is left snug but no pressure on the gauge at the dock.
800 to 1000, for everyday sailing.
Note B: backstay tension, along with other methods to shape sails, is NOT a function of "racing". Whenever you cross the starting line of a race as an official entrant, you are - at that point in time - a "racer".