I can see why you would need to drill some "access holes" to inject the epoxy. I did have one area where I wasn't sure I could get the epoxy far enough in and considered drilling a hole. I actually used a razor knife to "score" the ABS and open up a sort of flab to get the epoxy under the ABS. Any cracks that are wider than a "hairline crack" I use the ABS/M.E.K. mixture to fill. It has worked out very well so far. If you do drill holes I would simply keep them to a minimum...….the G-Flex will flow very nicely before it begins to set. I believe it has a "working time" of over an hour. Use a roller or simply press down on the entire area that has delaminated to get a good bond. Then put down some weights of heavy object to keep the ABS in contact with the substrate till it has set. Give it time to set.....don't be in a rush. After it has cured, either use the G-Flex or the ABS/MEK mixture to fill the drill holes. Sand smooth. Seal with a coat of Grizzly Grip or a good quality truck-bed-liner -----I'm using U-Pol's Raptor. It is a spray on liner that covers well and looks good. Keep me posted on your progress.