Hypothetical Matings

I also see that you posted about this mare a few years ago: https://forum.thoroughbredvillage.com.au/adding-speed-to-a-middle-distance-mare_topic62408.html

And here is a horse for sale out of Wild Hostess' half-sister by Tale of the Cat: https://inglisdigital.com/lot/30000155.27.htm

Based on Wild Hostess' production record and that of her half-siblings, I would not describe her as a middle-distance mare.  

IMO the reason the Deep Field mating was successful and the Excelebration was not is all about Mr. Prospector....specifically through Fappiano (Roy & Explosive) and sons of Mr. Prospector with the Rough Shod II family (Geiger Counter, Northern Meteor).  For that matter, Hussonet is a son of Mr. Prospector out of a Bold Ruler-line mare, as is Elusive Quality's sire Gone West (more on him in a minute).

With Deep Field, adding more Mr Prospector has been reasonably successful given opportunity -- Aysar & Master Hunter (Flying Spur), Isotope (Xaar), Hawker Hurricane (Fappiano via Bernardini), Chat (End Sweep), Aheadofhistime (Jade Robbery), Durham Star (Geiger Counter), Mr Mojo Rising (Bahhare).  Not all of the horses I listed are stakes winners, but they've run out at least $100k on the track which is a good general level of talent.  Sending Wild Hostess to him worked well enough to get a horse who is has won or placed in 40% of her starts so far.  

Back to Gone West.  Linebreeding to Secretariat has been tried a LOT, especially in North America where Storm Cat, AP Indy, and Gone West all stood at more-or-less the same time and their daughters all took turns going to one or the other.  The one that was most successful?  Gone West with another line of Secretariat.  His racetrack champion son Speightstown is also a very successful sire.  Violence, by Medaglia d'Oro out of a Gone West mare, has two Gr-1 winners out of Storm Cat-line mares.  Wootton Bassett, Gr-1 winner and now high-quality stallion, is from the Gone West sireline and his 2nd dam is Chief's Crown, who is out of a Secretariat mare.  

Elusive Quality, who is by Gone West and who is Deep Field's broodmare sire, didn't see many mares with Secretariat up close himself, but his best son Quality Road is racking up champions out of mares by Bernardini (AP Indy), Dehere, Hennessy (Storm Cat), and Malibu Moon (AP Indy). Elusive City, another high-class son, is the broodmare sire of Wooded, Beat le Bon, and Bucanero Fuerte, all by Wootton Bassett out of the same mare.

All of this is a long way to say, look for patterns and go with what works.  In your mare's case, Deep Field worked, and your mare's breeding worked for Deep Field.  His brother Shooting to Win and son Aysar are both in WA (which may or may not help you).  His son Cosmic Force is at Newgate for $11,000 and his first foals are running now.  Portland Sky is at Widden, but at $22k may be too much for this mare.