At 100mg, you will need to mix them at about 35 parts 25mg to 6 parts 100mg to get a 36mg result. It will dilute the flavoring some and likely add just a bit of TH. There are several
juice calculators available. They can really help in times like this.
My fav at this time is the one at
eJuice Me Up - e-Juice e-Liquid Recipe Calculator - it's an executable program for Windows. I'm not sure if it's available for other platforms.