Well, I don't know what to say. I have had to see sense and realise I'm just not a good mapper. This is a 'sense' quit rather than a rage quit, I see no more sense in trying to get this map to work; it's a failure as it persists in lagging in-game, in both SP and in MP modes despite my very best efforts and the efforts of others who've helped me. It's unplayable in its current state.
The map is lagging like a ***** and I just cannot for the life of me, work out what's actually causing it. I've spent many, many hours working intensely with the brilliant, patient Buggie, ridiculously clever Aspide and bot-pathing god Sektor and had advice from Hourences and Lode to hopefully get the map to state that I was happy with but I realise now that's not gonna happen, the map is, somehow, fundamentally flawed and I cannot work out why.
My only guess is it's a poly count issue, I know it's a busy map with lots of beautiful detail (if I say so myself) - did I push the engine too far? *Rhetorical question. The simple answer to my own question though is: Maybe, yes.
The map file is linked here with all the associated files. If you want to try and get it running smoothly, by my guest, I want no more to do with it. The link won't be active for too long so I suggest you save it and maybe make it available elsewhere but with this post attached so people know why it's being made available.
If you can work out why it's flawed and you can solve it without destroying the map's visuals and all of its functionalities, then you're welcome to release it, but only one version please. From now on indefinitely, I'm 100% washing my hands of it and UT99 because I have other things I wish to focus my attention on.
I'm done with mapping for UT, you'll not see me again. I've done my best with it and I have no more to give. Thank you to all who helped me with it and I'm so sorry it's come to this.