Gravtech's SQUID is 13.75 ly/h, or 330 ly per day. We have reports of Mass Effect drives (used by the Council races, at least) reaching up to .14 ly per day. We don't have any SPECIFIC values for mass-relay travel, however we know that they shorten trips of "years or even centuries" to "hours or days". We also know that the Secondary Relays are trips of up to "a few hundred lightyears", though Primary Relays can take much longer.
I think a decent assumption for Mass Relays would thus be 25 ly/h, so a little under double SQUID speed, but that may vary depending on what model the Relay is (since there are visible difference between, say, the Alpha Relay, which was the first one, and the relays that appear to be younger than the Protheans). A more recently-created relay might be able to go as high as 40 or even 50 ly/h. And that is for Secondary Relays, not Primaries. Distance involved with Primaries would likely mean they are much faster, but they are solely relay-to-relay movement.
No, the 13.75 ly/h was the max speed, they were discussing it before the launch. They were testing at various speed ratings, and stopped at 50% as far as we can tell. It probably took just under an hour to travel the just-over five lightyears between Alpha Centauri AB and Barnard's Star, at half-speed.
It already kinda is, given how it is an Omake Series. Maybe when MPPi finishes one of his stories, he can bring the Mass Effect Omake Series out of Omake territory and into Fanfic-of-a-Fanfic territory. Probably rewrite it, along with the Stargate Omakes, into a "Gravtech's Multiversal Misadventures (as caused and related to Taylor Hebert, Supergenius).
I have got to ask, where are you getting your data from? My calculations are based on the information on the Mass Effect wiki, specifically the pages on
FTL Travel and
Mass Relays. Your estimation would have them crossing the Milky Way
80.4 TIMES in a single hour, as it is merely 105,700 light years across. The LOCAL GROUP is only about 10M lightyears across, so you would be nearly traveling the entire local group of galaxies in an hour.