I would go for Sikaflex, but only because that’s the product I was recommended years ago & as a creature of habit that is what I’ve used subsequently.
My only reservation is it’s shelf life, or more accurately it’s life on my shelf. It cures in the tube & as I use it so infrequently it isn’t unusual for me to perform open tube surgery to allow me to scrape out what I want. And then of course it’s completely useless.
What impresses me most with the number of body jobs going on is the dedication to your cars & the dedication of the replacement panel manufacturers in making quality parts for a car that can still be bought for much less than a grand.
When I bought the f these cars were all but considered disposable items so cheap were they & by the number in the scrapyard the once proud owners thought the same.
When I did some of the jobs you chaps are on with, I took my battery angle grinder to the scrapyard & having found an appropriate donor zizzed out the required sections.
A recurring motif at that time was the reasonable car with a boot full of water bottles, indicating dead head gasket. The other saving grace for the forlorn was the rag top. Roofed cars were picked up by forklift & stacked, f & tf invariably we’re on the ground & with the roof up, so things were reasonably easy to access, if sometimes mouldy.
Those were the days, tool bag in one hand & carrier bag full of goodies in the other; 52mm throttle body to replace the old SU plastic offering for £15-00 & other trinkets thrown in.
M