Hi FizzleStix,
Welcome back. You sound like you are well on your way to becoming a full fledged BAR (Born Again Rocketeer).
Can't help you with the right coast stuff. I can help you with the Leviathan
First... Don't assemble the motor mount as it is in the instructions. Do glue the forward Centering Ring (CR), and the middle CR in place, but leave the rear one off. This will allow you to do internal fillets, which will improve the strength of the fins. Only then install the rear CR. Do not use the engine block, as it limits the length of the motor you can use. HPR motors typically have a ring of material along the bottom edge that serves the old engine block purpose.
Papering the fins will make the finishing process easier. [Edit]
I've found that a fin guide from Payloadbay works wonders on keeping those through-the-wall (TTW) Fins
at exactly the right angle is a cheap and efficient use of time to make. It's easy to use... Just enter in the diameter of the body tube, number of fins, and height of the fins, hit "Submit", and print out the results. Using a glue stick glue the resulting printout to a piece of foam core ($1) at you local dollar store, cut the slots and the space for the body tube, and you'll get very nice results every time. Caveat, these types of fin guides are not so good for surface mount fins (like the LPR kits you made as a kid), as they can skew quite a bit (if you're not lucky).[/Edit]
You can use the supplied launch lugs (LL) or install rail buttons (I recommend rail buttons).
Score some 30 minute epoxy (I like Bob Smith Industries stuff, 'cause I can find it at the local hobby shop (LHS). You'll also need some J.B. Weld (Home Depot) for installing the motor retainer. I like epoxy because you don't get the "pinching" that can occur with other glues when you're gluing CRs or Couplers. Caveat, use strips of masking tape to make sure that the coupler won't slide when you use epoxy to glue it in (otherwise, they can and will slide down into the tube if you're not careful).
Spirals can be filled in a number of different manners (I use RustO's Filler Primer). You'll find a lot of people here like RustO's Painters Touch paints. Krylon has changed its formula, and isn't what it used to be. If you're really into glossy finishes,
you might want to look up some of Nathan's builds.
To get the nicest possible nosecone, I recommend that you first "paint" it with a Sharpie, then wet sand it off with 220 grit, and follow that up with a wet sand using 320 grit. Prime and paint should be fine with that.
Here's a tutorial on making balsa nosecones (NC) look like plastic, the process is pretty much the same (except for the drizzling CA glue part).
Leviathans can be kinda tricky with its nosecone's slanted attachment point for the shockcord/chute, so you might want to fill, or cut it out.
Somewhere around here is a thread or 3 talking about how it has been known to vent the ejection gasses w/o deploying the laundry (and the lawn darts that result).
Stickershock has a reasonable costing set of decals for the Leviathan (I personally went with a dark red that matched the Rusto Sunrise Red perfectly).
Below is the one I made as a commission for a company (stretched w/an extra body tube), a "stock" Leviathan (unfinished), a tennis ball, and a schnoodle named "Murray".
All The Best!
Jim
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