I have been following your build a little bit and just saw the pics of the truck... WOW! That thing is clean. Sounds like it is going to be one bad ass truck!
With your conservative goal of 500-550 hp it sounds like you are going to have a lot of different options and routes you can go. I know you asked about vgt vs non-vgt so I thought I would chime in a little. Both options have come a long way over the last few years. Tuning, pricing, and options for both areas have increased greatly. It will come down mostly to your personal preference.
VGT turbos will typically spool sooner and faster. Many describe it as an exponential boost building ability. Your boost will go from 10-35psi very fast, almost instantly. This is loved and hated by some people. I personally love the feeling of a big vgt hitting its sweet spot and spooling up. Almost like a big 2 stroke dirt bike. Those same vanes that make the vgt turbo so awesome also cause some draw backs. They tend to flow a little less air way up on the top end. Also more to worry about with vgt turbos including sticking vanes, solenoids, etc... What we know now about maintenance, tuning, and the upgrades we have out help not to having those issues as much.
Non- VGT have also come a long way. There are tons of size options, different housings, better pipes, better tuning etc... these have really helped out the non-vgt department. Most describe the spooling a non-vgt to be more of a linear build of boost. Also they usually light a little later in the rpms (when comparing two turbos of similar size vgt vs non-vgt). But the biggest advantage IMO is that there are not vanes to worry about (for those that do worry) and they tend to flow much more up on the top end.
It will mostly come down to personal preference but IMO... for your goals and truck use... it sounds like a good medium sized vgt will suit your needs well.
190/30 and a 68mm vgt turbo should put you right about where you want to be and still keep it a clean awesome running truck. 190/75 or 205/75 will probably put you a little above your goals...
I know you also asked about injectors and nozzles. I know lots of people used to run huge nozzles when they were not needed and found out that their trucks became very smokey... Smaller nozzles go a lot farther than what people used to believe. For example 75% nozzles have shown to flow upwards of 230-240cc of fuel... So why would someone put 100% nozzles on smaller injectors like 175s or 190s??? I dunno??? but it used to be really popular. IMO you want to have a good ratio so that you can still make good power on a descent PW/timing while not having a smokey pig while towing or just cruising around town.