Ola Jack
Well it was a little hard to judge the Weathering from the pic you posted. I`m glad you posted the two bigger pics
First of all I have to say that using an old model as testbed is definately a good step to learn new techniques. I have my old tiger (my first armor kit) as testbed and so far it has seen numerous techniques of Weathering, Zimmerit tests, Snow tests etc. etc.
Ok Over to the weathering. In my opinion you have overdone it to say it quite harsh. The weathering is ok if the Tank is in the hands of a Guerrilla group.. They don`t care that much about the paintjob of the tank. If you were in Service some man with stripes propably already kicked you in the rear to repaint your machine.
People often tend to overdo paintchipping (I made myself guilty of that more then once) The Paint used on these vehicle, Certainly modern vehicles, were painted with paint that dries almost as hard as the metal surface it is painted on. This means that you almost had to shoot it or throw a big piece of stone on it to get a paintchip. Sometimes you see vehicles chipped so intense that you might think it drove through a meteorite shower.
A way to Weather is making use of Washes Drybrushes etc. I use a wash to more or less create a painted shadow on and in the deeper parts of the model. A wash is basically nothing more then heavily diluted paint (usually dark colors) that you run over the complete vehicle. letting it run in the deeper parts and dab the excess away with a piece of Tissue. Don`t smear/whipe it off because that becomes a mess.
With Drybrushing you can more or less highlight the higher parts of the model. With the drybrush you apply a little paint to the brush and you whipe it on a piece of cloth till almost no paint comes off. Then you gently stroke over the higher parts leaving only a little paint at a time. USually the drybrushing is done with a lighter variation of the basecolour to give an idea of wear and tear.
Adding chips. When Adding chips make sure you do it with diluted paint and take a dark color. Best is a sort of darkgrey I usually only add black chips when working with panzergrey underground. With a small brush you make tiny spots here and there. Making a pattern with the chips always looks a little odd. Just put them on random but also on places where they are logical. Mudguards, Glacis, the sides, Around hatches etc.etc. Think of the places that can easily damage. Why Diluted paint for paintchips? It dries completely flat. Remember a paintchip is a damage in the basecolor and there the paint is chipped away.. Never a paintchip can lay on top of the basecoat and sticking out a little. which happens with paint that is not diluted.
Last but not least (my personal Favourite)........... Filters. Basically a filter is almost the same as a wash. but there is a difference. I use filters to make small changes in the basecolor. Because a Filter is more diluted as a wash it shows the basecolor through a transparant (colored) layer in which it shows a bit different. Applying more filters on a model makes the basecoat come more varied and shows more signs of wear.
I have a good article on using Filters by MIG (Miguel Jimenes) who is an absolute master in using them.
Put a filter in your life by MIG Also check out his other articles about the weathering of vehicles. This man is somebody you can learn a lot from.
MIG`s Rarities I kow this is quite a lot of text and there is a lot to learn on this subject but believe me investing some time in learning them improves the models with 1000%
I hope my explanation is of some use for you.