I think you just answered yourself in your own post, there, @Heihachi_73

Not so similar, really, especially when each variation means another part to change/die to cut etc.

Wolfpac

I am resigned to now realising I need to buy a couple of these locomotives.  

Are the locomotives DCC ready with space for a speaker as I would like the locos to have sound.  Is there a preferred DCC sound chip for this locomotive and have users here completed a sound conversion as yet?

If they were doing the H sets, they would have announced it and shown off a 3D model already. Also, I can't see why they would only do one and not the other (e.g. electric vs. loco-hauled) when they are practically the same cars. Granted, the blue Harris cars would be a bit more fiddly to design/build with the numerous vents on the roof, not to mention there were a number of shell variations - 1st series, 2nd series, Grey Ghost, 2 or 3 doors per side, 2 or 3 windows per section, 60 foot, 75 foot, regular BCH, short van BCH (ex-Grey Ghost motor) and probably even more differences - AFAIK the Harris bogies differ slightly too, at least compared to the "regular" Commonwealth bogies underneath S/Z/N cars (assuming they use the same).

Your right, but nothing stopping them from being selective?
The first series regional conversions could carry right through the range of colours worn, and add the long car variations perhaps as extra 2 pack sets. Add the van variation as a single pack and the displaced short cars can then be added to form a third set. However if you want genuine set combinations and car numbers, it all turns into a nightmare, unless you can alter the  numbers easily.
Remember the decal set numbering system of 20+ years ago? Are they still about? You set the white numbers up and transferred them to the model by rubbing the back with a pencil. Mine are still in good condition up to 30 years after. They never took on commercially in the model field, were purchased at newsagents in a range of sizes, colours and fonts. If an enterprising manufacturer revived this system with complete car set numbering and templates for positioning it just might work.
Rod

I am resigned to now realising I need to buy a couple of these locomotives.  

Are the locomotives DCC ready with space for a speaker as I would like the locos to have sound.  Is there a preferred DCC sound chip for this locomotive and have users here completed a sound conversion as yet?

Bevans
My DCC sound system has the lot, including individual HEP controls I willtry to do a video today, but look here, Mike does not seem to have one up. You can get cheaper generic sounds, but this one rocks!
DCC sounds of Australia
I will do a short video this morning when I unpack mine
Cheers
Rod

I am resigned to now realising I need to buy a couple of these locomotives.  

Are the locomotives DCC ready with space for a speaker as I would like the locos to have sound.  Is there a preferred DCC sound chip for this locomotive and have users here completed a sound conversion as yet?

Hi Bevans,

I think I may have your answer, I just posted a video on YouTube last night in regards to installing DCC sound into this locomotive.

Here is a link to the video



https://www.youtube.com/watch?v=_OEhkupwCcI

Hope that helps.

Cheers
Luke.

EDIT: Just saw your private message, lol. Glad I could help.