i did mine by removing roof and sides ,peeling roof cutting section out of roof rejoining rest by rivets ,removing rear door section of roof,relacing that section with ally to give a straight rear roof line then on sides i took rivets out of section that joins sides with rear side windows ,once seperated i cut sides to suit roof bent side ends 10mm to re rivet rear side window panels back on used 50mm box section from one side of tub to other .30 mm to make a box frame all around rear inside, then riveted a prepared 3mm ally sheet where top of rear door would of been,and chequer bulkhead panel in lower ,or tub part..shes solid and dont leak.
i drove it for a week like this but knew i needed at least a rear window so finally got a rear and two sides made ,mini front window seals and filler strip cut to length jobs a good un lol..the glass was toughened and cost 40.00 the two strips etc 30.00.
no filler,no fibreglass just etch primer and paint. took my mate and me 7 solid hours of work ,but worth it .no its not finished inside but the hardest bits done ,my mates removed his bulkhead for roomier cab ,ive only got short legs so didnt bother..
with paint,rivets etc prolly whole job 130.00
hope this helps ,although not very good at descriptive stuff so just ask lol
trev