I've managed to find my files with limits for the S-70s I flew until 1998 (where did those twenty years go?).
These were copied from the RFM, unfortunately I don't hold a copy of the actual document.
Cabin Doors
May be fully open up to 100 kts with soundproofing installed aft of Station 379.
May be fully open up to 145 kts with soundproofing above removed or properly secured.
Doors not to be intentionally moved from full closed/open position in flt. Only in hover. If doors move in flt then they can be positioned open/closed
Gunner's window fully open to 170 kts.
Cockpit door sliding windows not to be opened/closed at any airspeed.
Flt with cockpit doors off prohibited.
I can vouch for the "vacuum cleaner effect" of the cockpit windows. My newly amended and fabloned local area map went out over the sea one dark night....it was ripped straight out of my tight fist before I could even blink!