Not a type 1 fire pilot, but feel i've asked myself the same thing.
Money vs Job Satisfaction.
Collecting a fat check is really nice but from what I've seen in the type 1 field, there isn't as much flight time, or mission versatility. Its water only. I work along aside an Erickson contract that flies 50 hours a year. A YEAR. I understand all contracts may not be slow but if its a tough season, you may question your decision. Look at this fire season, or lack thereof!
The company I work for has a couple Blackhawks and I've asked myself the same question, Should I push to jump up? what will i gain, what will i lose? I've done some utility/construction in them but I personally love the freedom and versatility of mediums. I work with a FS Helitack crew thats social and fun and ever changing. As a type 2 pilot, I feel I get paid well, and can say the same thing for other big medium companies like HQ, or HeliExpress.
If you feel you need more money, no shame in trying to bump up the pay, but if you feel like you want experience and stick time, maybe stick with the lights/mediums. I can't say you will get paid more as SIC unless you head overseas. Columbia pays GREAT if you want to do 30/30 in Afghanistan.