G’day BL,
With the YMEN ILS DH at 351’ HAT and a 3deg G/S being 325’/nm I figure that on slope at DH you’ll be 1.08nm/1900yds/1740mtrs from the glideslope antenna. I think you used the DH altitude in your calculations instead of the HAT.
Now the glideslope antenna, or more specifically the glideslope ground intercept point, is usually around 300mtrs from the runway end so on slope at DH the runway end should be 1740-300 or 1440 mtrs in front of you in which case you should be able to clearly see the HIRL and threshold.
I hope this explains it and that I haven’t got my maths wrong.
Regards,
BH.