Welcome to eventing!
The suggestions can’t really start until we know more about you: are you tall? Short? Do you prefer wide twists, narrow twists? Blocks? What about your horse? Tall & rangy? Mile-long wither? No wither?
I personally would avoid adjustable gullets… They really only work in rare cases and I have seen more harm done than good by well-intending owners.
My first saddle when I took the plunge into eventing was an older Ainsley - It’s either a Chester or a Leicester (I can never remember) - it’s a 16.5 and has been one of the most versatile saddles I’ve ever owned. It didn’t fit one of my TBs too well but it’s a great interim saddle. I did everything in it from fox-hunting to dressage rallies as a kid…
It’s the saddle I use whenever friends come to ride one of our guys, or someone needs to borrow a jump saddle locally. Everyone has loved it - it’s very flat and balanced and all of the gals I’ve had ride in it have remarked how secure it makes them feel… and it’s very close contact with the horse.
The older Ainsley models are more like Millers and Crosbys so may be a nice nod to your upbringing (Hunters). Mine has no blocks and a very flat but deep seat and wide twist. I love it and still ride in it from time to time. It’s oiled up so nicely people mistake it for a french saddle despite it being as old as me…
You can snag them online for $200-800 and they really are a steal… just make sure you get a wither tracing first from your saddle fitter.
By and large, the most reliable saddles for eventing seem to be Passiers and Stubbens.
My personal favorite saddle ATM is a Stubben Zaria – but as a beginner I think you might want to look at some older models before taking the plunge into an $$$ saddle.
BTW, Not sure if it is relevant but most eventers use the same saddle for jumping and XC. Three saddles is too much! :lol: