Allow autocomplete option for one of the levels

Hi,
First of all thanks for the awesome module - please keep on developing this much needed module!

Here's my feature request:
In the settings for taxonomy vocabulary HS, please create a new option for admin to potentially allow Auto-complete per each Level.

Here's the problem that I ran into: My Level 1 terms contain about 700 terms (and it will probably grow into 3000+), but my level 2 terms per each item contain about 10-20 terms. In this case, while HS will work perfectly for Level 2 terms, using HS for 3000 terms in Level1 becomes very-very user-unfriendly. Could you possibly add an option per each level to make that particular level Autocomplete?

Over the last 2 weeks I've tried and tested every module available to make this autocomplete work, but none of them allows for a combination of Autocomplete and drop-down choices like in HS.

Many-many thanks!