I don’t think there’s a standard that I’ve seen.
To me, it would depend on who you’re looking to hire. I’ve worked for equity in the past and was never worried about health care. Now that I have a child it’s a bigger concern, so that may shrink your hiring pool and those that will apply.
In your shoes, I’d let the salary/equity mix you are able to offer be my guide. If you’re asking someone to work for considerably below their market rate, then someone who’s considering that probably isn’t as stuck on healthcare. If you’re offering a decent salary and really want the best candidates then I’d do the research and figure out what your costs would be, then discuss it with the person you eventually want to hire as part of salary negotiations. In ads you could say you’re willing to work out a compensation package that works with the right person.