Let this be a warning! Avoid the venom smart temp at all costs!! it is a POS! quite seriously I almost lost close to $1500 worth of car with one of these little buggers! They rattle apart within no time and break down just as quick.
I'd recommend just a regular failsafe and use a temp gun separately. But it goes without saying that you should not tune to a specific temp. Some engines like to run 280F and above normally. Just make sure you are getting maximum power with lots of smoke.
In regards to temps, you can always do the 'spit test' where you drop a bit of spit onto the head and watch what it does. If it just sits there, its too cold, if it sizzles and vapourizes instantly its too lean. It should bubble a fizz for a couple of seconds before evapourating.