Good question Chris. I think for a light rehab the money is all made on the buy, though it is affected by whatever direction the winds of the market take you during your rehab period.
Ex: If you buy a $1mm triplex with 75% down and do a $100k rehab, but only create $50k in equity (making it worth $1.15mm) you'll be able to pull out 1.15mm x 75% = $862,500. Which would leave you with over $200k in the property with the math as follows:
$862,500 - $750,000 original loan = $112,500
$350,000 initial investment - $112,500 (from above) = $240k still in the property
However, if you are able to lock down a great deal off-market / distressed and buy the property for $900k the numbers get much better.
And to wrap up, this entire process will take 3-9 months. If the current ARV is $1.2mm and the market moves up 5%, your new ARV will be $1.26mm but if it pulls back 5% your ARV will be $1.14mm. So as you can see you are also at the mercy of the market!
Happy to chat further or take a look at any specific properties you have in mind!