MRC PRO acquired // need Mentor!

[Orph3o]

Hi everyone,
Name is Thomas, I live in Montreal Canada.

New to crawling, not to RC (truggy racer here).

I just bought a used (not so much) Losi MCR Pro.
MCR Pro+Mongoose 18.5T
some alum hopups.
one Rhino 2s 360Mah

I am reading as much as I can on this MRC section, searching and else, however, I have to admit that I would love to find a Mentor that could help me getting where I want to go
I am the "perfectionist on a budget" kind, trying to get the most out of what I have.

I am a friendly guy and I love sharing knowledge. As this crawling thing is new to me, eager to learn and share!

Here is a list of questions...

Batteries:
1) Ok, I can see that I should be using the LOSI 2s 600Mah on the front (side of the Servo). BUT, this is SO expensive compared to others...
I am looking at several options (Zippy Compact etc...) however, size is usually around 55*13*30mm. I have tried to "mimic" this and it seems it is not fitting in the front (wheel touching it as it goes way too far).
Suggestions on batteries and location? I was thinking of putting the ESC on the front links...
2) Using Mongoose 18.5t. Benefits of using 3s over 2s? Do I need to change pinion or gear ratio if going 3s?

Front/back links support
I have seen on pics people having some kind of a "hammock" between the links where ESC is fixed. What do you Use?

Servo
Just like for truggies, I bet a 400+ torque is the best ;) however, I see many people using a 645 hitech, is it enough for this size?

Tires/weight
My MRC came with Losi tires/wheels. However, the owner did not use foam in them and added "fishing weights" inside the tire (so moving inside the tire).
What would you advise?
I was thinking about adding blue+memory foam on top and using LOSA99201 inside the wheel.
Would love the Losi alu Wheels, but 100+ is a bit excessive to start with, maybe later

HopUps
Based on my readings here, some hop-ups I am considering right now, can you confirm this is worth it?

1) Reverse Tranny to free some space in front.
I read that the more weight/components you can fit in front the better, I am trying to have everything as close to ground/front as possible... now is this too much? an ESC in the back is this bad?
2) Outboard shocks (LOSB1446)
3) 8mm wide hex drive (LOSB1721)


Thanks so much for any help!



Thanks for any help you could provide!