How Do Subsidies Work With Uncertain Income?

We would need me my husband and our three year old covered ? My husband is a boilermaker he goes on jobs every month. They may last anywhere from 2 to 3 weeks or he may go on one for 8 weeks. And it is not always with the same employer. The income changes he may make $2800 one month and $4600 the next we just never know. We have looked into other insurance plans and they want anywhere from $800 to $1400 a month and that just isn’t possible. So my question is if we are not sure what his income will be month to month and if we make more than what we thought we would we would have to pay a fine then is it safer to just bump up our yearly income and say we will make 70,000 or so and make less than that in order to have insurance with y’all and not get in trouble for lying ? bc we honestly won’t know how much he will make.