Typical rates for CFO advisors range from $60 (for a controller) to $250 (for a strategic CFO). I would guess $100 / hour would be market for this type of work. Alchemist might have partnerships w/ Countsy and maybe Mercury interactive that might be relevant.
You don't need to give equity. You can just negotiate a cash rate. If you are cash strapped, you can either do a cash rate and negotiate to defer payment until you raise $1 million. If you need to do equity, I would infer what the equity would be by taking a $100 / hour rate, multiplying it be the projected number of hours of work, and dividing by your post money valuation cap. If you don't have one, assume a $10m cap. So each hour would be 0.001% of equity, and I would cap the number of hours they could spend.
I would solicit a few offers and then decide. You can look at the perks spreadsheet for some guidance on providers here, although the sheet may be outdated.