501X build questions

[Howard1650]

I've finished building my TRF501X WCE- great car - but have a few questions -

1) I've shimmed the bearing / drive shift / wheel hubs, but there is still some play in the axel is this normal? The hubs are the metal type.

2) There is play in the ball cups, is this normal? (What is the best replacement, make & part number for the cups and balls please?)

3) How tight should the diffs be? How do I measure or 'feel' the correct settings? (Will the surface made a difference?)

4) Who sells the 'diff housings' to help keep dirt out.

5) How tight should the slipper be?

6) What is little to break, wear etc in the first few runs?

Thanks