The Owen Woolley designed (circa 1970s), New Zealand built Raven is a whole lot of boat packed into 26 feet. Specs on the Raven here: https://www.ravenyachts.com/ravensdownsouth.htm
'Fantail' (above) is a Raven that was converted to Junk rig by Annie Hill, a holder of the esteemed Blue Water Medal and the author of a couple of well known books 'Sailing On A Small Income' and 'Brazil And Beyond'. 'Fantail' was sold a while ago to new owners but you can get more information about 'Fantail' (her conversion to Junk Rig etc) and Annie Hills current Whangarei built boat 'FanShi' here: https://anniehill.blogspot.com/
Video of 'Fantail' under her new ownership is here: https://www.youtube.com/watch?v=9akBxOv9xFg
The diagram below showing the comparison of the current junk rig with the original masthead sloop rig shows that in terms of fore and aft 'working sails' there is not much loss of sail area. Of course what is lost in sail area is more than made up by handiness and simplicity. In the same manner as the gaff rig, the junk rig is powerful down wind.