Thanks everyone for your feedback - I think I will just need to risk it. Given the high loads on the flights to MEX (mine currently shows J1C1Y1, the rest zero'd, and the day after the same) I will try everything to make it to the gate before the door closes as rebooking to an earlier flight is just not possible given the fare difference.

I guess the determining factor will be the wait at passport control - if that line is short I will probably make it even with 30 minutes delay, yet when lines are long there then I probably even have an issued when everything is on time. In terms of assistance - does KLM offer something like gate-pickup only (so no wheelchair service, but only these carts that move people around at AMS), and if so - can I book that online, or do I have to call?

Greetings - Dirk