Ross, a big Welcome to FOG!
Over the years Festool has done very well adjusting TS55 at the factory. Less than a week after I purchased my first TS55 in January 2006, one of my best friends also bought one. By then I had followed the instructions and trimmed the splinter guard on all three of my original guide rails. My pal brought his new TS55 and rails to my place. It turned out his saw was adjusted to within 0.1mm as mine. Frankly that is as close as we can expect even with CNC machines.
Subsequently I have bought 4 more TS55, built in different years. One was different from my original TS55 by 0.3mm, so we did adjust it. The others are within the 0.1mm tolerance.
Way back when most of the alternative TS55 blades did not have a uniform 2.2mm kerf, as do all current Festool TS55 blades.
Several of my employees personally own TS55. Normally when working in my shop and using my guide rails they use one of my TS55.
Perhaps I have been very lucky that the only two guide rails I have purchased since Festool switched to the clear splinter guard are factory drilled for LR32. Those could be used with the TS55 but in my shop hole drilling happens in a different area, so my LR32 guide rails never had their splinter guards trimmed.
By the time I needed to replace older splinter guards Festool had started using the current adhesive. The nice service folk at Lebanon HQ suggested making sure all the old adhesive was removed and the place be cleaned with MEK or acetone. Just before applying the new splinter guard we gently warm the rail with a heat gun so it is just slightly more than room temperature. After applying the splinter guard we make sure the guide rail is resting on a smooth flat surface at the outer edge of a work table. We then place a 1x3" batten on the top side and use gentle spring clamps to maintain pressure for an hour.
I have not had a problem of splinter guards separating from guide rails. I must say my own guide rails do not leave my shop, where the temperature and humidity are controlled, since I opened my shop. From 2006 until mid 2010 most of my rails were transported to various sites and rented workshops frequently, without problems of the splinter guards separating.