Is there any way to configure Tixati to prioritize the first and last piece of each file like uTorrent does?  Thanks in advance for any and all help with this!

look here
https://support.tixati.com/settings%20-%20transfers%20-%20files

sequential download options, press configure button.

what do all those properties mean? aggressiveness, progress limit..

Minimum seed count = how many seeds the torrent must have for the preset to be used
Aggressive percent = how aggressive you want the file to be downloaded sequentially
Progress limit percent = how much of the file will be downloaded at the aggressive percent
File tail MB = how many MB to download for the tail of the file
File tail percent = the percent of the file downloaded for the tail

Im pretty sure this is how these options work.

thanks, that was useful. could you describe more how the aggresivenes affects the transfer?

I will assume numbers here.
100% aggressiveness = strictly sequential
1% = almost random pieces

utorrent's "play video as it downloads" used strictly sequential and led to many 99% dead torrents, because nobody downloaded the rare last pieces. If your download speed is fast and there are enough seeds (avoid risk of killing the torrent) then you should be fine with default values or a low aggressiveness value.
It'a reasonable to assume 50% aggressiveness means 1 sequential piece for 1 random (rare) piece.

Tixati already prefers first and last pieces because that's how most file formats work.