Yeh BM20. I was having results similar to yours, not quite as bad tho. More 40 mins. So I took it out in frustration but thought I’ll try it again with the original tap. I have a conical too so was prepared to go without.
I mainly hop stand with my immersion chiller. Brew brite at 10 mins. So chill to 80, take out IC then whirlpool with hops for half hour, add the chiller back and everything is settling while chilling.
A few things. When I installed the helix back in I did make sure it wasn’t too tight as I think that could be a problem. E.g I raised it a cm or so opposite to the tap to lengthen the diameter a bit, insert it as far as I could into the copper join etc. When whirlpooling stir around the middle stalk as close as possible, not out as far as the electric coil. The tap I think helps so it doesn’t suck the whirlpooled trub back to the coil.
All up 5 - 10 mins to fill the conical, even tho the original tap doesn’t flow as much as a ball valve. My 2c and hopefully I keep getting the same results.