I have spent a lot of time lately discussing the merits of buying land and building or buying an already built home in a similar location. Ultimately the decision comes down to two factors: Location and Time.
If you have time, as much as two years, between now and the when you want to move in then the custom build concept could work. If you have less time, like one year, then you will likely b disappointed when the timeline fails to materialize. My recommendation is that you do not pla to move into a near-finished home while the final touches are being applied as it will take the shine off of the excitement of your new home. You can have exactly what you want, how you want it, but someone has to be available daily from the start until the end for decision making otherwise timelines stretch dramatically.
If location is is your primary concern and you have your heart set on a piece of land then this becomes the key factor since we cannot move the land. Seems obvious, but maybe there is a similar location that gives as much or similar utility that has a nearly new home on it with similar features. School districts often drive the final decision or proximity to amenities, but these districts are broad and with some looking a fine alternative can often be found.
Building is something most people want to do at lest once, and most of those only di it once....
Oakville and Lorne Park offer some spectacular lots for building from 1/4 acre to 2.8 acres and beyond.
Having what you want in the end is what the goal is. Sometimes building works and other times buying works best.