A word of thanks up front.

I have installed cabinets a couple of time for easy kitchen remodels
but I have come across a challenging (for me at least) installation
dilemma.

A typical installation requires one to install the wall cabinets, base
cabinets and then countertop. The challenge, and sure a lesson, is
that I have a cabinet (appliance garage) that is suppose to rest on top
of the countertop.

Base Cabinet - 34.5"
Countertop - 1.5" (ideal, we are going to tile)
Appliance Garage - 18"
Wall Cabinet - 36"

Is there any trick to the trade for installing an appliance garage and
getting the correct measurements so there is not a gap either between
the appliance garage and the wall cabinet? This assumes that the
appliance garage "rests" on the countertop (obviously secured to
the wall).

One option, not a favorable one, is to install the base cabinets, the
countertop and then the wall cabinets. This way you ensure no gap
exists and you can ensure all wall cabinets are of equal height.

Are there any other options available to me?

Any information would be much appreciated.

Thank you !