Your boson has m24*0,5 lens mount, it is similar to one of flir tau, you can find some lenses from it on ebay. Chinese usually have m25*0.5 or m34 mounts. afaik 0.5 in flir differs from 0.5 in thermapp/chinese, lol, get ready for surprises and experiments. tau has bigger case and shutter so i guess you wont have problems with back working distance but chinese make really different and odd lenses) i have 35 1,2 and 50 1,0 from them with m25 thread
and yeah, that lines from boson datasheet about changing lenses and quality tolerances bother me too, you need it for UAV or just thought it is small and classy?)
about TA pro - i have usual TA, chinese m25 lenses fit it perfectly. wider ones might be not capable of covering vga resolution though