I've been reading the forum since I started with the fiddle 4 months ago at the age of 72.  I just joined the group as I thought perhaps I could add some useful information on humidification.

We live in Wyoming.  High desert.  Our house has a boiler and hydronic heating.  I've been playing the banjo for 7 years and looked into options to adding humidity for the their comfort as well as ours several years ago.    I researched humidification solutions quite a bit and arrived at a solution that works well for us.  We were mainly interested in the healthiest solution for us more than for instruments at the time. I learned that fiddle require a bit more attention in regard to humidification.   I think the saying that, if you're happy, your instruments will be happy, too.

Evaporative humidifiers with wicks are recommended for health reasons as opposed to ultrasonic or misters and put quite a bit more moisture into our house.  We chose the Aircare humidifiers. 

Our house is 3,800 square feet. An upstairs and a finished basement.  As there are only two of us and the downstairs is only used when company comes, we had one Aircare upstairs.  I bought a second as a spare (in case of a breakdown) and we use it upstairs as well.  Less trips to the faucet to fill the tanks that way.

We keep the upstairs (where my fiddle and banjos reside) at 40-45 humidity until the outside temps drop to around 10 degrees.  We then have to reduce the units to a lower setting as we'll get condensation on the windows.  For when we have to adjust the humidity lower, I bought some Boveda humidity packs to put in my fiddle case and this keeps my fiddle at 40-45 percent.

We use "BestAir" Golden Solution humidifier combo solution treatment to help the wicks last.   We have well water that is naturally soft so don't have many problems with mineral deposits as long as we stay with the Aircare wicks.  I've tried several after market, lower cost wicks but found them lacking.  I refill one, 1.9 gallon tank per day.

I hope this helps someone.