Hi,
We're also TTC #2, this is cycle number three. DS was a big surprise
I started temping last month and am temping and using opks is month.
There are benefits of each:
Temping - helps for long term planning, only a one off cost for the basal body thermometer, which has two decimal places, best way to confirm ovulation after the fact.
The negatives are that you have to do it at the same time every day, before you get up or move and you ideally will have had at least 3 hours sleep steaight. This is easy enough using an alarm and having the thermometer by the bed.
Temping only confirms ovulation based on a sustained thermal shift of at least three days so you won't know when you ovulate until well after the fact.
Opks help predict your best fertile times at and just before the time.
I think they are great together to be honest.
If you have fertility friend, there is a wonderful charting your way to fertility course it does which takes you through a lot of different fertility signs to monitor.
Good luck!