The room list has been published here: http://thehifishow.com/guide do your research now and you can prioritise the rooms you want to visit based on the types of equipement in use.
A few tips:
In the rooms you're interested in, try a few different seats in the room as the set up won't be perfect and you might find yourself in a room null / peak and not get a good impression so move about a bit. Also try a minimum of 2 tracks before deciding to stay a bit or move on. Mark up your guide before and during so you know which rooms to go back to.
It a bit of a warren - treat the building as 2 halves - the old building which has most of the larger rooms - ground and first floor, with the stairs to the first floor being just opposite the reception. The new building is best accessed through one of 2 less than obvious doors - see the guide linked above. One is just to the right of the Private Dining Room and involves crossing the courtyard to the door diagonally to the right. The other is to the left of the stairs at the left of the private dining room you go straight through 3 doors and then turn right along a covered walkway and through another door into the new section. Once in the new section its essentially a 2 floor L shape so you can work along one floor, change floors and work back along the other floor. The only anomilies to this are the Gun Room / Rutland Room on the ground floor and Syndicates 23 and 24 on the first floor, so watch out for those.
If you want to maximise your time, take some sarnies as its a fair schlep back to the "restaurant" which will be selling burgers and sarnies.
May be start and the far end and work back, if you're there first thing as many just wander into the rooms nearest the doors and they get crowded
Be polite enough to smile / nod / acknowlege the room hosts. You might like what you hear, it might by OK or you might think its awful - that doesn't matter, the room hosts deserve a thank you for spending their own time and cash to be there.