A few queqstions before i start

[jojo]

First i'd like to say hi!

I registered here today but i own the book for about 2 years now.
I havn't started the build yet but i'm hoping to do so soon.
Meanwhile i'm doing all the perparation work i can, like figuring out the amounts of steel to buy, which length's to cut from one length of steel to make as little loss as i can, things like that.

I do however have a few questions that i need answered before i want to continue:

1) I'm 1 meter 88 cm's big (6 feet 2" ?). Not extraordinary big but not too small either. In all the picture's of finished builds the seat seems to be placed as far back as possible already. Will my length couse a problem with legroom if i don't modify the chassis?

2) All the plans show steel sizes, but not always very specific, the 25x25 i found by research on this forum to be 1.5mm thickness. The internal diameter for the wishbones i found in the book to be 12.5mm. but i can't find the size for the rear panel tube's (rp1, rp2, rp3). 12.5 internal diameter seems a bit heavy duty for these parts. Same goes for the 19x19 RHS, i can't work out the thickness for those either but suspect they are 1.5 too, is that correct?

3) The donor will very likely be a sierra but i want to use the c20xe engine from vauxhall. Will that engine fit into the chassis good without sticking out of the bonnet and is it hard to fit a gearbox for that engine into the chassis?

Thats all i can think of right now, but i'm sure i'll be back with more questions later

Thanks in advance, Jonathan