Financing rate depends on the loan amount. Granted, a 70% margin is low-risk to the bank due the customer having to pay 30% for the property, the rate is heavily attached to the loan amount.
Do you have any other commitments? If no, here it is. Also assuming that you are younger than 35 years old. Most banks will consider 80% of your monthly average for the variable as well as rental income; while some banks will only consider 50%. In the calculation below I am using 80%

You could do that, there are a few ways about it. Legally speaking, as long as you are upfront about it, then no issues. But if you go through the "loan compression" route, that is already in "grey to black" area already. Either way, as long as you do not have more than 1 residential property loan under your name, your next application(s) will be given 90% maximum margin of financing (MOF)

Just to be clear, can you share these details? Easier for me to get it done right at once:

Personal
Name (or nickname):
Age:

Income (RM/month)
Gross:
Nett (after deducting EPF, PCB, SOCSO):
Variable income (OT, commissions, if any):
Rental:
Investment (ASB, Tabung Haji, Unit Trusts, FD):
Bonus 2017:
Bonus 2016:

Commitments (RM/month)
Mortgage:
Hire purchase:
Credit card outstanding:
ASB loan:
Personal loans:
PTPTN: