Xtal Oscillator selection question

If this topic is out of place for this forum, I apologize.

I am using a HCTL2032 Quadrature Decoder/Counter to interface a rotary encoder to an Arduino Mega.

I am uncertain how to select the proper clock Oscillator. The IC is rated for 33MHz. Should I use this

value? In the past I have used its ancestor, a HCTL1000 with rotary encoders (from U.S. Digital) with 1MHz oscillators

with good success. My application is fairly low speed, < 1000 rpm.

Any enlightenment will be appreciated.

Vic