I distinctly remember reading a report/interview that Reinbacher did during this 2024 pre-training camp golf tournament with the Canadiens in which he basically said that he's had quite the growth spurt since his draft year, was 6'3 in training camp right after the 2023 Draft, and is 6'5 now.
Can't find that article/mention though, it's buried under 5000 articles about Reinbacher's major injury in Late September of 2024. Also under metric tons of comments people made bemoaning the pick and whining about not selecting Michkov.
Anyhow, Reinbacher did have to deal with Osgood-Schlatter disease (caused by growth spurt) in his knees during his D+1, wore braces in training camp, and was visibly slower/clumsier on the ice to start that season in the NLA but got much better as the year went by and he eventually dressed for the Laval Rocket.
Disturbing development concerning David Reinbacher: he is suffering from a disease that is causing serious problems in both knees
So yeah, I don't know about any comparisons to Mrtka as both players are pretty different in their playstyles, but current-day Reinbacher would be pretty close to the same height as Mrtka.
And to not get completely derailed by this "out-of-nowhere Reinbacher excursion", I do like Mrtka's game in the WHL but would like to see him more aggressive against the puck-carrier.
Sometimes I think Mrtka gives attackers too much space out there.