Understand that if you are classified as a non-resident of Montana, you will owe Montana a tax-return for your income earned while physically working or living in Montana. If you are classified as a resident, you will owe Montana a tax return that reports and pays tax on all your world-wide income, even though you are also a resident of Florida which has no state income tax.
Fortunately, Montana determines residency using the concept of abode, and does not appear to have a secondary definition based on time. So as long as your residency in Montana is clearly temporary, there does not seem to be a time limit that would make you a resident if you exceeded it. You should review the Montana definition of "permanent place of abode". Remember that abode is determined by the weight of the evidence, there is no one single test. But you want to avoid steps that would tend to inadvertently establish a Montana abode.
https://montana.servicenowservices.com/citizen?id=kb_article_view&sysparm_article=KB0013204
