F6 shocks.
I will check in my parts catologue tomorrow. There is probably a strong chance that an F6 will have a higher rating shock absorber, but it will be exactly the same dimensions as an ordinary GTL/F4, I would think. The chassis is longer, the anti-roll bars are thicker, and the van body maybe slightly heavier, and it is rated to carry a greater weight. However if your intention is not to carry much in the way of goods, a decent GTL shocker should probably suffice? If not, I am sure a site on french ebay might stock F6 shockers. I will let you know the part number too. Does your F6 have anti-roll bars on the rear suspension too?