Hi Dirk, if your goals are early planing and easy gybing - for sure the Gecko. You don't mention your sail sizes or weight/experience/local spot fresh or salt water - but given you want to use it light winds, I'd say the 122 makes more sense than the 110? Perfect for 10-20 knots more or less, you can also use it in more wind with smaller sails.
The LTD is indeed stiffer and lighter, so better for planing yes, there is some planing performance loss. So I would always recommend the LTD if you can afford it, otherwise the HRS is also a great value for money product and is also more robust for knocks and crashes. If you get the LTD and are not 100% confidant with catapults etc, then get a nose shield, either the standard one or the lighter EVA ones from ION/other brands that you can just stick on - used that with my kids on their Gecko´s when learning and made a world of difference to nose damage!