I've run Bosco's with Sram GX 2X10 triggers mounted in 2 different positions.
Originally mounted them right above the brake lever and grip, in the "standard" position. This worked fine for shifting from the grips and was comfortable but the shifter got in the way of wrapping my hand around my favorite hand position on the Bosco: the downward curve of the bar that's right ahead of the main grip area.
I then moved the shifters farther forward on the bar, past the bend and mounting them on the downward slope of the bar. Inspiration photo from Riv:
And WOW, do I love it. It's extremely ergonomic when riding on the curve of the bar (which I tend to be in most of the time). It allows you to fully wrap your hand around that curve and get some serious out of the saddle leverage (while still being able to shift) and it's not much of a reach from the swept back grip area.
Downside is that the shifters are a huge eyesore in that position and look really klunky/out of place, but whatever!
I also angle my Bosco's down quite a lot so that may play into it but I highly recommend giving it a go! I really like trigger shifters and think they function great on the Bosco (aesthetics aside).