I too have thought about this as my boot does not stay open very well.
As space is limited and getting a gas strut in is going to be tricky how about a pair of torque springs
constant torque springs.jpg
Taking the right hand drawing you bolt the bit on the left to the half of the hinge that supports the trunk/boot and then just needs a peg on the fixed bit
They come in different spring rates but only the thickness of the spring varies and if one spring is not enough just add another.
I have a spare trunk/boot hinge so will take a look when I find it to see if it fits.
FYI: a middle of the range spring runs on a R3 of 31.75 mm with a RA of 99mm and exerts a force of 28.5 kg/cm add another and you double this figure.
Bob
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