I think you are over complicating.
My climate temps and HR varies between both extremes and all I have is a digital device that cost me 16€... And never felt the need for anything more than that.
I agree with rbarata.. don't overthink this. Most orchids will acclimate to a range of temperature/humidity. What is important is first learning about the general needs of the types that you have, then try to match as closely as possible the areas within your own environment with the needs of the plant. In most places in the US, spring is a very good time of year, because the overlap between indoor and outdoor conditions is not that large - this gives you room to experiment a bit. You have multiple microclimates within your environment, both inside and outside. Look at how the sun moves through the day. Where are the trees? Do outdoor walls provide shelter or do they radiate heat and light? Figure out what you have before you worry about how to adjust.
Welcome! I agree with others that have said you are overthinking this. As far as a humidity monitor, I have several AcuRite humidity monitors that are digital and they cost about $6 a piece. It reads the indoor temperature of the room and the humidity percentage. You'll get an awful lot of good advice here on the OB. Good luck.