I would do 20% and either
- withdraw from the brokerage account(remember to factor in any taxes this may incur for the year)
Or
- Continue saving until you can get the 20% without a withdraw
IMO PMI is a big waste of money, it also can be a pain to get out of even if you hit 20% in initial equity(may require reassessment, if market drops could require a lot more equity, etc...)