I know what the guidelines are and have recently qualified clients for this product.

Any other general principles or guidelines or advice you may have for me?

They shifted their guidelines and are not doing Rental HELOCs right now. 

Guideline allows 1 FHA loan at at time unless exceptional hardship **

Comps in my market have become a "guideline" since everything is selling well above list price.

I've heard/read that it needs to be held 2 years, or it needs to be on at least last years tax returns and also that it can be averaged out at 75%.Anybody go through this recently that can shed some light on the actual guidelines?

Well, if you've got the HUD FMRs for your county, my understanding is that HUD will NOT pay more than that number (less the UA = Utility Allowance).The H/A gets the HUD money and uses the FMR as a guideline and may make vouchers less (so they can do more vouchers) or more (if there is a real shortage of 4 beds like the other person noted) with some extra funds.

Thats not investing thats gambling.  

There are lots of guidelines and potential loopholes around this though, and definitely need to understand ways to possibly navigate.

To pass an inspection it has to meet FHA guidelines.