I've been evaluating this keyset for Finnish/Swedish keyboard layout on macOS and I've identified a couple of smaller issues. I'm using the Finnish locale, but to my understanding the actual keyboards from Apple are identical for both Finland and Sweden (I'm not sure if the Swedish locale would produce different alternate characters). A bit late to point these out at this stage but I'll comment these anyway since I did not spot these in the earlier discussion.
The keys 4, 7 and 0 on the numerical row cannot be matched with this keyset to macOS FI/SWE layout. For my purposes I won't be needing function keys or the numpad area so I'm ignoring those entirely (but they seem OK).
In this layout the shift+4 should produce a € - symbol, while option+4 produces $. Therefore for FI/SWE layout the keyset should have a "4" - key with € - symbol at the top. The closest option for this key is the one from INTL kit with dollar symbol at the top and euro symbol at the lower right corner (so the currency symbols are in a reversed order for this layout). A preferred alternative would be a "4" - key with Euro symbol at the top. Apple themselves omit the Dollar alternate symbol.
The second issue concerns the curly brackets and the keys "7" and "0". On a FI/SWE layout three types of brackets ("()", "[]", "{}") are produced using the keys "8" and "9" on the numerical row. Combined with shift these keys produce the round brackets, combined with the option key they produce the square brackets and together with both shift and the option key they produce the curly brackets. Therefore the keycaps for "8" and "9" in the INTL kit are OK, but the keyset does not have options for keys "7" and "0" which would omit the additional curly bracket legends (the ones in BASE kit have incorrect alternative symbols for FI/SWE layout).
And for the sake of completeness, on a FI/SWE layout shift+7 produces "/", option+7 produces "|", shift+option+7 produces "\". Shift+0 produces "=", option+0 produces "≈", shift+option+0 produces "≠".
I'm new to this so cannot say if this in general is a known issue and just a consequence of the difficulty of matching all possible layouts. Seems to me that one additional key (a "4" with Euro on top, perhaps omitting the secondary alternate character, but if one was included it could be the Dollar symbol) and a change to two keys (omit the curly bracket legends from "7" and "0" in the INTL kit) would have made this set compatible with FI/SWE macOS layout. Or alternatively if the legends from "7" and "0" could not be removed, perhaps two additional keycaps would have been needed in the INTL kit to cover those as well.
I don't think these are dealbreakers for me and I can live with the inaccurate legends on the three keys, especially since I'm sure my locale is in a minority here. It was so close though...