Regarding an oil temp/pressure sensor, remove the oil dip **** light sensor at the back of the head and install a T fitting, one end goes to the dip **** sensor, the other end goes to the sender of your gauge.
For coolant temp, you have multiple options, but I think the most elegant one is to find a gauge with a scale that can be configured by the user. Then use the output of the stock sensor and feed it to the gauge.
An alternative would be an OBD2 bluetooth dongle, paired to a phone/tablet/gps that feeds all the OBD sensor data. You'll miss out on oil data. Alternatively you can use a PC-V and POD-300 to get everything you need to know with 12 gauges you can configure in one device that is incredibly convenient.
In my opinion, oil pressure is a "idiot" sensor, i don't mean that to be derogatory, allow me to explain. If your oil pressure is off enough to notice, damage is already done, it's too late. It's not a warning sign it's a symptom of damage, better is oil analysis at oil changes, it can give you a hell of a lot of data otherwise impossible to get without tearing down the motor.