I wonder if you are going to ferment the gherkins first, as in the US recipes? if so, a good link was published here a while back, I've kept it, here it is:
http://www.uga.edu/nchfp/publications/usda/GUIDE%206%20Home%20Can.pdfbut you will have to do it their way, and translate the measurements.
I've found you can pickle them safely another way, but the taste isn't the same as you get in shop bought gherkins, they're a bit sharper, but it's acceptable to me.
Wash the gherkins thoroughly. Slice into large chunks. Soak in brine made with 50g salt to 500ml water for 24 hours in fridge, pour off the brine, make up some fresh brine and soak for another 24 hours in fridge. Drain off and keep gherkins chilled while you make up the vinegar. For each 100g of gherkins, you'll probably need 150ml of good quality vinegar, I use white distilled malt vinegar. Heat the vinegar in a pan with your spices. Place the gherkins into warm sterilised jars, then pour over the spiced vinegar, and lid them immediately. I use new jars and lids. They are ready to eat in about 4 weeks.