Could I feasibly utilize online GEDCOM user-tree-to-user-tree merge services like MyHeritage (and Ancestry) with GRAMPS? I’m envisioning having to routinely export my local .GRAMPS as a GEDCOM and then upload it to those services, where I use their features, then export another GEDCOM, merge them, and hope that nothing went wrong:
If not, I’ll probably just have to make do with a lack of insight from the services, but it’d be convenient if there were a way that I’ve not considered.
Not really, IMO. And the main reason for that is that Gramps does not support a merge on UID, which most other programs, on-line and off-line, do support in some way or another. UIDs were introduced by PAF, I think, or maybe Ancestral Quest, of which PAF was a free version, and most programs export those with the _UID tag, although I think that Ancestry uses UID. My Heritage also exports those, but My Heritage UIDs are shorter than the standard set by PAF.
If you really want to merge a lot, RootsMagic is a much better choice than Gramps, but you have to use that on Windows, because the latest version has problems with Wine that we haven’t solved yet. And with we, I mean fellow RootsMagic users that I meet on the RootsMagic discourse forum. I use an older version here, which can communicate with Ancestry and FamilySearch, and show hints from Find My Past and My Heritage, and that version has a duplicate finder that works pretty much the same as the one in Gramps, with scores, and is a bit smarter too, because it merges duplicate events too. Gramps doesn’t do that, so you will always have to clean up duplicate events, even if the dates and places are the same.
RootsMagic has a bulk merge in the paid version, and that looks quite good.