If you are looking to put standard AK handguards on a Saiga rifle, and not use "half-assed" bolt on components, follow my guide. It details fully how to convert a Saiga to AK furniture using proper Soviet parts. Linked in my guide are also my detailed guides on front sight block removal, replacement and centering, as well as a guide on pinning a muzzle brake.
https://proxify.com/p/011010A100010...52d66726f6d2d73746172742d746f2d66696e6973682f
Having done rifles using both AK and Saiga forends, bolt on and actual Soviet, I can tell you I actually prefer the factory Saiga handguard and find it more comfortable and likely just as durable. It's some insane fiberglass resin with steel reinforcement plates inside of it. Second place IMO comes to standard hardware and dead last are bolt ons.
Last year I made a little bit of money making and selling bolt on retainers made from original pressed on ones at a very reasonable price through CSS. They are OK and work good if you cut the groove for them in the barrel. However they are not as durable as originals and I (or anyone) who would tell you they hold up to as much abuse is incorrect.