I use about 400mm of M6 threaded bar it worked for me it then cost me £1 for 10 door pins. since then I have now bought the proper tool from Portland tools.
The Kit I used was a steel bar with a slot in one end and some steel pins, the steel pins are inserted through the hinge pin and a small knurled nut screwed on, the bar is then added with the pin in the slot, a tap on the bar with a hammer then has the effect of pulling the pin downwards, there were different sizes of pin in the kit and the pins were available separately the BX needed the thinnest pins in the box and they were looking a bit the worse for wear after swapping four doors, sorry I forget the brand but the kit was easy to use, sorry about the rambling description
Stewart
TZD 19 TD one of the few
Xantia Td estate, going soft