Trying to get back into 40k, modelling and painting, plus a plan to focus on getting me there...

So I got back into 40K in the last few years but only fleetingly, I appreciate all of you who gave me advice at the time and hopefully still follow me. I have also been loitering round the blogs so have spoke to some of you if not actually doing much myself, for a number of reasons I wont bore you with!

Now I want (need!) a plan to focus around, I have a lot of half done models and ideas and it's about high time I turned them into an army! (and stop buying stuff like an addict on eBay!)

I originally wanted an Imperial Guard foot/gunline based Army but found A) in the few games of 6th I played it was, for me, seriously boring to play and B) I like spending a lot of time on each model so having 100's to paint wasn't a good plan! C) I found out I really like converting vehicles.

So having gone back to the drawing board in an effort to get re-enthused in playing, but also have a building/painting plan, I've put together the 1500 point mechanised list you see before you to aim at putting it together as a balanced starter force:

HQ
Leman Russ Command Squadron – 365pts
Leman Russ Punisher - Knight Commander Pask
Leman Russ Executioner

Elites
Militarum Tempestus Platoon -250pts
Tempestus Command Squad -Plasma Pistol; Plasma gun x4
Militarum Tempestus Scion Squad - Meltagun x2

Troops
Veteran Squad 1 - 190pts
Grenadiers, Plasma gun x3
Chimera - Heavy Bolter; Multilaser; Heavy Stubber

Veteran Squad 2 - 190pts
Grenadiers, Plasma gun x3
Chimera - Heavy Bolter; Multilaser; Heavy Stubber

Veteran Squad 3 - 185pts
Grenadiers; Krak Grenades; Heavy Flamer x1; Meltagun x2
Chimera - Heavy Bolter; Multilaser; Heavy Stubber

Fast Attack
Vendetta - 170 pts

Armoured Sentinel Squadron - 150 pts
3x Plasma Cannon

Total - 1500pts

So..........the worries I have about playing the list, even with my lack of experience, is model numbers and lack of template and blast weapons. I feel as a minimum I should probably buy a wyvern and massage the points to get it in, but at the same time I don’t feel that fits with the rest. I’m after a mobile elite force, I want to get in peoples faces by advancing and dropping in behind rather than wait for them to come to me. I just worry it’s maybe a bit of a glass hammer I’m trying to hit them with?

I’d appreciate some comments on its viability from those in the know, one of the hardest things I'm finding about getting motivated is the catch-22 of, I need to build the models to find out if it's an effective tactic vs I don't want to spend time on models I'm not going to use.

I have all of these models so that’s one of the reasons I have picked them, but I also have many more options from the Guard available, ratlings, rough riders, CCS, a platoon to name a few so I’m open to some tinkering, but I want to remain mobile and try and avoid a gunline. I feel I really need to find points for a hellhound but not sure where I'd get them without compromising something else.

Thanks in advance for any advice and suggestions, I have always found this a generous community, please bare in mind that I want to keep my initial model count numbers fairly low as modelling time is at a premium.