Oh, also I've never really used these adhesives before - would one tube be able to do about 16m of picture rail? Or will I need to buy more? I really have no feel for this!
I have used a few of these different products Pink Grip, Grabs Like Nails come to mind, but the only one I will use in future is "No More Nails". Grabs well but not instant so you can move the item a bit to fine tune position. In coolish conditions, gives you just the right amount of time to apply the stuff, fit the rail and locate accurately. Don't dither about though to be safe. As others have said it will not hold well enough if either the rail or wall are well off straight. Have found N_M_N on offer in local Boyes shop, otherwise it is one of the dearer ones.
Would be inclined to put two smaller beads of adhesive on rather than one big one. Check the tube for the coverage claimed.
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