Guys, don't get too technical. Lets go to basics, if all your jumpers are using square mains and reserves then the exit point becomes less critical in winds up to 15 - 20 kts. Start with a WDI and work out the upper winds from the met forecast. As a rule, they veer with altitude so if you calculate the spot from the WDI, the exit point should be deeper and further right in the northern hemisphere ! Get an aerial photo, divide it into squares, use a grid system and alter the spot accordingly during the day - ie C7 maybe moves deeper and right to D9. Use the GPS and spot from the front, espescially if your Van doesn't have a side door. The other technique as used in the States is to calculate a deep ish spot and run in cross wind - then all the groups have a chance of getting in as they simply funnel back towards the DZ. Message me for more info and we can chat if necessary. Yes Javelin's are the best kit !!