HOW MUCH YOU NEED TO EXPECT YOU'LL PAY FOR A GOOD THERMTEC VIDAR 660L 2.0

Will it fit Alright on the Tikka T3X & regular Picatinny rail……is there nearly anything I should evaluate to ensure ? It's unclear to me if an prolonged rail is desireable or not.I've my S10 on the Tikka T3 and it requires an prolonged rail to get your head in the proper place. Also, the supplied nuts with the screws attaching the mount for the