As new AIIMS are being added this year(tentative till now), it’s hard to say how much the percentile might go. Last year it was 99.57 for UR, 99.16 for OBC and SC 94.57 and ST 93.65 percentile. This year it might slip a bit ranging from 0.5 for UR to 1 in SC and ST.

Marks can never be predicted as AIIMS never releases the marks corresponding to rank. I would say a marks with 140+ is safe from my personal experience.