Vacant Lot - Offer contingent on development financing??

[Mike Watkinson]

For an offer on a ~$150k vacant commercial lot, is it common to include a financing contingency for the lot and my proposed build out? I will already need to make my offer contingent on getting a conditional use permit for what I intent to do, which is an approved conditional use but needs to get plans approved which will take around 6 months. 

If say I make the offer contingent only on financing for the lot itself and zoning conditional use approval, is it common to show some pre-approval/qualification like you would for a residential property? Or is it more a blind trust thing for these types of deals? 

I'm just looking for some opinions on what is the norm since I'm getting some "yes man" vibes from my agent and I haven't purchased a commercial property before. I don't want to get to aggressive on the offer and give them reservations about me tieing up the lot for such a long approval process.