Ok Doing a lease option just want to see if my #s are ok

Brand new house was listed for $1,050,000 w/ a realtor. THe listing is expiring in 2 weeks or so. The landscaping is bieng done after that so that may take 2 weeks or so. SO I have a verbal agreement to buy at 900,000 or so. 2-4yr lease of 3000 a month. Probably a 3000 deposit which I will make out of my tennant buyers option deposit. My exit is Lease option for 1,100,000?± Purch price, and $4000 a month lease w/ a 20-30k Option deposit if i can get it. Keep in mind this is in southern cali. So this is not outrageous. The house is in a brand new luxury community and they have all sold for 900,000-1.2 mill. And the area still has good appreciation rates. Am i out of line here? Id be happy with the upfront deposit and monthly cash flow, even if there were no back end. Im just wanting some input as this is a bigger deal with somewhat unfamilar rental rates in this caliber of home. Also I am structuring it so that I will not do the deal until I get my tennant/buyer and the seller demanded a % of whatever I get on the back end which is still to be negotiated. Thanks for any input!