Lighting in a Detached Garage

Go to a real lighting store. Often times they'll consult with you free of charge if you purchase the fixtures there. They may cost a bit more, but are usually of higher quality than the big box stores and you get the advice. If you buy enough, sometimes they'll bend their policies a bit and give you contractor pricing. Clearly you need design input and they can give it to you, right down to calculating the lumens per square foot you need as well as other lighting options, such as task lighting.

Also, many lighting stores are small, locally owned businesses worth supporting. IMHO.

If you want to spend more money, sure, an architect or (more specifically, and perhaps cutting out one superfluous factor) lighting designer can multiply the cost of your project by X=Large Factor.

If you'd rather not spend so much, testing and evaluation are good. Look at LED lights you like. Find out what they are, or what specs you like for color temperature at least. Buy one or two, try them out in the space - see how you like them at various spacings. Plan from there. If you do a good job figuring out first (from store displays or friends' lights) what you like you might not need to do much testing to find fixtures you actually like, but having a few and TESTING the spacing is really helpful.

Circuits for LED lights - you can run a LOT of LED fixtures on one 15A circuit if you don't put anything ELSE on that circuit. One circuit per floor is probably quite adequate; one circuit for the building might well be adequate. At a typical 10 or 20 watts per fixture, between 72 and 144 fixtures per 15A 120V circuit (derated for continuous load.)

If you end up with a few extra test fixtures, you'll probably still come out money ahead - you can also sell them off.