Here's one that I've used on various OBs through the years. I too prefer using a water pressure gauge vs a temp gauge.
https://www.surplusunlimited.com/mm5/merchant.mvc?Store_Code=1&Screen=CTGY&Category_Code=700-25
Also discipline yourself to look at it everytime you start up and glance at it when changing RPMs (as it will move) and whilst running ... soon it will be 2nd nature to glance at it quickly every so often.