I used a Wintec 500 on my safecob with great success. I tried another very expensive option but he made his dislike of it very plain

and he deposited his rider promptly and was humpimg his back when I tried it out. I assumed the person fitting the saddle was qualified (Iknow, I know - very dangerous!) and he certainly charged enough for his service. I took the saddle back, laid down the law and actually got a full refund when I challenged his status. I didn't know it, but he already had a court case pending because he was being sued by a client with a similar complaint! Thank you, unknown client!
I reverted back to the Wintec and he was back to his normal kind self. Sadly, my wonderful Sabre saddle did not fit him and I sold that to a friend for her TBx - Sabre saddles were fantastic but sadly are no longer made. I used leather saddles for most of my riding but for the since 1992 have used either Thorowgood or Wintec saddles.
I have tried treeless but did not like them and, like Erica, found they slipped on just about every horse I know whose owner uses them. I kept one horse at a yard that was very "natural" (silly description in my view, but there we go!) and out of 6 owners 4 used treeless of various makes and they all had slipping problems and spent vast amounts of money on various pads to try and make them stick!
BTW, have you looked at the safe saddle website? There is a link on the Safecobs website. They are produced with biggies in mind.
Erica - when I was a young gel (and I am quite an old f**t now!) most of the saddles made had a serge lining. They were the devil to keep clean as numnahs were rarely used then! Once dry they had to be carefully but thoroughly brushed and were reflocked regularly.