You are correct, 'Impulse #1 was April 1995. My bad.
Wikipedia gives Max Mercury's first appearance as May 1993 in Flash Vol #2 # 76.
https://en.wikipedia.org/wiki/Max_Mercury
[He first appeared in Quality's National Comics #5, cover dated November 1940, as Quicksilver.[1] Comics historian Don Markstein calls Quicksilver "probably the first imitator of the Flash's super-speed schtick.[2]
Almost nothing was revealed about that character except that he possessed super-speed. On the identity 'Max' Wikipedia quotes [Koolman, Mike; Amash, Jim (2011). The Quality Companion. TwoMorrows Publishing. pp. 170–174] but incorrectly. This reference deals with Quality and also with later DC interpretations and revisions of the Quality characters. Koolman dates the name Max from the DC era. More interestingly, he credits the art to Nick Cardy [Viscardi] in nearly all the Quality Quicksilver stories. Some later ones are signed. This makes sense to me.
Link to the book:
National Comics 30