Williams FP-70 target knob conversion help

I'm trying to change out the "hunting" style knobs to Target style knobs which are available from Brownell's and others. The issue is what size (length of screw) to order and none of the sellers can help. There are long and short knobs available. The Williams FP-70 TK (target knob model) comes with long elevation and windage knobs. Has anyone made the conversion from a standard sight to a TK that can help?. It seems to me that ordering long screws would be correct but the Brownell's tech asked me what length screws are in my standard sight and I don't want to take it apart until I have replacement screws as there is a detent ball and spring that I only want to mess with once.
Thanks, Don

Go to www.williamsgunsight.com

Find the 800 number and you can order the TK screws for replacing the standard screws. Will cost some pennies.

What's the cost of both sets as opposed to what you want to do? Use the correct one and return the other or put it in your loading box.

Thanks,
Called Williams and spoke to a guy that knew what he was talking about. The windage, elevation and "Gib" lock target knobs are in the mail!
Don