I would wait till you get your highsteer. This way you can set every thing up at the same time and make sure it all works together. Highsteer clearance is usually the limiting factor on up travel so it is nice to have it installed when you set up your suspension.
The only thing I know about push pull steering is how to remove it so I can't offer a lot of advice there. When people are talking about shortening the drag link I'm assuming they mean cutting and re-welding it. If you are going to do this I would recommend having it welded by a professional. If you do it yourself sleeve it. I have a nice miller welder and consider myself pretty skilled but I would not be confident welding steering components.
