Depends if it fits the pony. Not best quality but reputable brand so you could trust it was reasonably well made and won't hurt pony as long as it fits. Even though these are the slightly adjustable its still needs to fit tree size.
I used one last year to back a pony. It fit her well, was lightweight and comfortable. As soon as she was backed, hacking out on her own and basic schooling, I had her fitted for her first English leather saddle. I think if it fits your pony well and is checked by an experienced person then the amount of work you are planning on doing it would be fine.
Hi Lite saddles are made in India, the stirrup bars, dee rings and saddle nails are not strong on these for starters. Panels and girth straps tend to fray and stitching pulls through the seams on the panels, apart from that they are tough but don’t seem to have much other appeal!*