We are doing MIST/LISA from 24 weeks onwards. We use sucrose en facilitated tucking, wich works fine in most of the cases, and, if necessary (rarely), atropine. We do not use any other premedication except caffeine, of course. But it remains an issue. If a baby is too vigoruous we switch to INSURE with propofol sedation.
The colleagues in Leiden use propofol, 0,5-1 mg/kg I think. They published a paper in 2018: https://pubmed.ncbi.nlm.nih.gov/30068669/