No need to rule out internal routing. I’ve drilled 3 frames for it now with zero issues. You have to be a bit careful obviously.
I think the main thing to watch with the longer posts is whether you have enough insertion space available. If you have an interrupted seat tube or one with a bend for example this becomes an issue.
I was in contact with Cotic before I bought my Rocket trying to figure out if I could fit a 150mmm Reverb. In the end I was fine with a 125mm. I don’t think a 150 would have worked for me at full extension at my height. Borderline anyway.
It’s defo the geo of individual frames. I had a Transition Trans am before and was fine with a 125mm dropper. Moving to my PP Oka, I really needed the extra drop of the 150. Both 27.5″
Perfect now.