A few things to consider in terms of loan structuring:
1. Ensure you set up all your loans as I/O (as Terry said). Given your relatively higher incomes, you may have excess day to day funds to deploy somewhere. You may want to pay some of it down, best to do it by putting funds in an offset account. I/O set ups increase/preserve your borrowing power significantly. Banks work out your borrowing power by calculating your 'surplus' income after expenses are paid. Going I/O reduces the expense calculation in plenty of borrowing power calculators, and thereby increases your borrowing power.
2. Start by crystallising this goal and seeing how property can get you there. For example, 'I want to build a $5mill property portfolio in the next 8-10 years, mainly purchasing in growth areas close to CBDs etc'. Once you've down that, you can build a finance plan to match those goals. To be fair, your broker you sat down with may have asked you this and then came to the conclusion LMI is not necessary. Its generally a very useful tool to build an asset portfolio quickly, but blanket advice of 'always use LMI to start' may not be appropriate to your situation. Generally it suits most, but most don't start with a $250k income and $250 savings pool.
3. Depending on what comes out of point 2, consider the pros and cons of LMI early. With $250k in savings available to you, you may not actually need to use it if you plan on a slow accumulation phase. Alternatively, if you're looking to build up that asset figure as quickly as possible, utilising LMI and stretching that $250k further is definitely a good idea.
4. If possible, get some idea around how you'll build your portfolio over the next few years. This again will depend on goal no 2. With your incomes though, you may have significant surplus income available and your borrowing power is likely to be strong. This may assist in focusing on lower yielding, more growth focussed assets. Most on relatively lower incomes need to achieve some sort of balance between yield and growth to grow their portfolio. You may be able to weight one side of it more than the other with that income, but this type of discussion will need to be considered holistically.
5. Basic loan structuring. Picking lenders appropriately, going I/O, not cross securitising, etc - this will stretch you out further down the track and save you from potential headaches.
6. Consider diversifying over time.
Cheers,
Redom