How much should I ask for build-able lot?

[Sam Ray]

I've wholesaled property in the past and I've learned to keep the purchase price + repairs + my fee around or under 65% of the ARV. Usually my buyers were generally happy with this price.

Well I've just come across sellers who want to sell build-able lots, I've never wholesaled lots before which has put me  grey area of understand on what to offer them. I read somewhere that getting the purchase price (plus my fee) around 1/3 of the value of the house after construction is completed is a good place to be. Is this generally accurate?

Most houses in the neighborhood in question, on similar sized lots are selling around $145k. Would $40k-$45k be a good offer range?
Thanks!