It can be very difficult to create nice seamless loops into samples. Without crossfading it often is impossible at all.
So I have to export the samples to edit them with another audio-editor. It would be very usefull if the next version of Polyphone makes it possible to use a lineair crossfade and a power crossfade.
I usually work on my iMac at home. Despite I own Logic Pro X with its improved sampler features I find it much more intuitive to use Polyphone because it lets me easily zoom in or out.
On the PC I often use the free software LoopAuditioneer to create seamless loops. (It's main purpose is to find the loop-points itself, however in practise I find that function disappointing and time-consuming. With its crossfading function you can create nice seamless loops.) This program is on Sourceforge. Maybe that can be of help for the programmers to add a crossfade-function?
Nice to hear something from you! I hope everything is alright.
If I am allowed to give you a suggestion about the development of Polyphone: I think you can help people the most with extra information about soundfonts and its possibilities.
About the crossfading: creating loops remains a challenging thing anyway and one often needs an external audio editor for good audio samples. For the loops I presently rely on Endless WAV from Björn Bojahr.