Determining IGE hover at altitude  

Every aircraft type has their own rule of thumb rules if you don't have time to grab the chart. Hopefully during training they passed those along to you. If you can't remember any of those then safest bet is to attempt an OGE hover at that altitude and if you can accomplish that then you know when you start the approach you will have it all day.  Most of the time unless you have a fairly open area you are landing in you are going to need to have some OGE ability anyway on the way in and almost for sure on the way out so that's what you really want to know you can do.  Only being able to HIGE vs HOGE into an offsite LZ is how you get yourself stuck. Then there are a host of tips and techniques to fix that one too that dont include the race towards the trees hoping to get ETL and then pull up to clear, a few good videos out there of what happens when that goes poorly.