frequency counter mod

[VK5KAF]

i have an older 1 ghz frequency counter i built many years ago(will count to about 1.7ghz) .in general it works pretty well  but suffers from frequency drift  and lack of input sensitivity which i think can be improved by adding an elcheapo ebay wide band amplifier, My question is i will soon have a gpsdo at my disposal if i replace the 10 mhz crystal with 10 mhz gpsdo will this improve frequency stability and if so where and how should i inject 10 mhz  at pin 24 (iICM7216A) or remove the existing crystal and replace with gpsdo
Cheers and thanks for any input
John
VK5KAF