Hey jessenej -
here's my input for what it's worth. My 2010 RB V10 gas engine van is at SMB right now starting the conversion. I'm getting standard RB-50 floorplan FYI. I did the same thing youre doing now - the research and posting, etc. I love this forum and it's the main reason i am getting an SMB - the community out there is fantastic resource and people.
1. Jessenej - unless I missed it, you didn't mention a penthouse. From you're post, you definitely need an (electric) penthouse to accommodate youre family of 6.
2. My van has LSD rear and I'm putting ARB locker up front. This is my understanding: Firstly, when driving on paved (or any road for that matter where i'm not in 4WD) and van starts to lose traction, the LSD locks up automatically and both rear wheels get power and hence traction, altho more power goes to wheel slipping, which is lame because that's the one losing traction so why not send more power to one not slipping? Secondly, it is the transfer case that sends 50% power to front and 50% power to rear when you put in 4W hi or lo. Because we have manual hubs, we have to get out and lock them (first?) if we actually want 4WD because, as you said, the wheels are spinning free otherwise. That is because most of time you don't need 4WD so hubs s/b unlocked for less friction, less wear, less rolling resistance, better gas mileage, slightly improved steering feel (feels lighter possibly if you can tell at all). If you have auto locking hubs and it isn't full time 4WD system, then when you switch to 4WD you're system automatically locks hub for you. Otherwise, they stay unlocked for the reasons mentioned above. Most trucks today are "on the fly" type so you can go into 4WD hi while going 60 mph. Nice! Thirdly, the locking diff, in this case my ARB locker up front, will transfer half the front power to each front wheel when I lock it. That's 25% of the total power to each front wheel. Since i'm in 4WD, the rear has 50% power and LSD now and the hubs locked so almost as good as a locking rear diff when traction becoming an issue. It is the locking front, however, that is the most powerful tool you have now to get out of trouble because each front wheel, independent of each other and the rear, has 25% of the power PULLING you. This set-up, btw, is what Alan Feld, the owner, has on his rig.
3. Dynatrac rear axle - tons of opinion and so on on this forum for the need for a floating rear axle. This is prolly controversial, but after my research on this forum and how I will use the van ... which is way off-road but i'm not hard core rubicon rock crawler dude, I decided not to spend the money - very expensive - if i couldn't justify the expense, even as "insurence". I have an RB size van, like you do, and perhaps an EB waaaay loaded down would be better off having a floating rear axle. And perhaps if you towing heavy stuff you need it. I don't think you will get a definitive answer on need if you have EB and/or tow. I also have neither requirement. I put the money into electric penthouse and ARB front locker. I dont know if Alan has floater on his van, but if he does, .... well ... he has everything anyway.
4. Deaver and Bilstein - again tons of opinion and hard "before/after" data on why to do it. I say if you want Bilstein do it because they will put on what you want and credit you the price of the OME shocks. But YOU have to specify (and buy/deliver -which is no big deal) the shock and give them specs and make sure SMB says they are ok and will fit. I decided to go with their standard set-up and see how it is first, use it for awhile under all different conditions. For Deaver option you have no choice with SMB - you're gonna pay SMB for their set-up and if you want Deaver you're gonna have to go to Deaver afterwards and spend the additional money to upfit it. You're gonna pay Deaver anyway so I say do the Bilsteins then ... the cost of doing it that way is the price of the OME shocks but now you get to use standard set-up first to decide.
5. I think you said you live in/near Fresno. Have you talked to Alan Feld and/or toured SMB yet? If not, tell Alan you're thoughts on what you want and why, and get his input on the 4WD stuff for SMB.
Welcome and I look forward to some SMB road trips with SMB'ers. If I'm off on my understanding here, people will reply and fix it!
Warholic