You can borrow a lot more principal with much less interest.

@Chirag Rathod Just to clear out, since it looks like you don't own a property at this time, I would suggest that the first property can be bought as a principal residence with a 5% down and then if the plan is to buy a second property (after a year), that will also qualify for a 5% down payment with mortgage insurance.  

They shouldn’t be counting the principal or interest against you.

The closing date is stipulated in the P&S agreement you have with the seller, so is the earnest money(minimal) and which attorney firm will handle the closing (your attorney firm)The assignment fee is payable by the buyer to you after closing costs are accounted forYou as a wholesaler are assigning the contract to the buyer who is going to step into your shoes as Principal to the initial P& S agreement with the Seller.

Most will require a 20-30% downpayment.For mid-sized loans ($5mm+) they may allow you to bring in some equity, but will require a certain percentage to be from the Key Principals (guarantors) and will require about 10% liquidity to be maintained through the loan term.How large is the loan?

I am comfortably able to double the amount I pay on my principal each month and still save a nice chunk at the same time as I want to buy another property in the next few years.

Your payment won't change but your principal owed will change faster.

Principal is down to 117k @ 4.3% IR.

I understand that you can only transact as the principal, but can you collect commission when you buy?

IF you don't have the net worth to qualify on a loan of commercial size even with the property income, consider bringing in what's called a "key principal" aka. someone of high net worth to sign on the loan with you.