should also only be used with SLX or Saint chainring bolts, the heads on those are bigger
Ok, just to clarify, by the “heads are bigger”, you actually mean the bolts are longer, right? Can’t speak for the Saint, but the SLX chainring bolts (M665 and M660 – just measured both) have the same diameter head as normal – 7mm, which if you think about it makes sense or they wouldn’t fit in the standard recess in a chainring. But, they are longer (12mm vs 8mm) so that full thread is engaged despite the extra thickness of the bash over a standard chainring (or thin alu bash).
Just as an aside, my E-13 Turbocharger came with a set of longer chainring nuts, so you can still use the standard Shimano chainring bolts, and have enough thread engaged. Just another way around the problem…