New builder with questions (J5mk1)

Hello,
I am expecting my J5 kit this week, and have read twice through the manual already.
I am not completely a beginner, I have already done a mic preamp almost 10 years ago.
However one thing that confuses me a bit is checking voltages. I understand sometimes you have to do it between + and - on a part, and sometimes with the ground?
I'm not lazy but I'm not sure what to read or look for to understand these:

"a) At the rectifier (+) 358V
b) Output of the power supply board => C17 (+) 358V
c) Heater voltage (red against white wire) 7,4V"

"Now these voltages (+/- 5%) are to be measured at the taps of the power
transformer:
a) Primary
Pins 2-6 230V
b) Secondary
Pins 8-9 265V
Pins 11-12 24V
Pins 13-14 7,4V"

Now, I'm sure I'll have more questions when I actually start building the kit, but that is all for now.
Thank you to who will take the time to answer this (probably very basic) question.

Thank you,
I have come to the same conclusion after reading more on the topic, but it's good to have you confirm it!

Hello!
So, I've started building, everything is going OK so far, well not great but OK.
However I noticed I've received 500 pF instead of 470pF caps for C4 and 11, should I worry about this?
Thanks!

I see, thank you both for your replies.
I have finished the main board, and PSU and drilled most holes in the case, but as I'm reading through the rest of the manual again and again, some things are not very clear

• The plastic roller for R27 at the star ground point. I'm a bit confused by the word "roller" first, this is a small plastic cylinder, but mostly by the fact I can't really see it on the pictures. Aren't there some higher resolution pictures somewhere?
• "Then connect both electrolytic caps (-) separately with the star ground point, please use one lug there for the two green wires." Those from the PSU board, right? I'm a bit unsure because there's a ground symbol next to R9/- on C8
• Everything's that AC: heater, primary, secondary windings, as long as I'm connecting the correct pair of lugs, it doesn't matter which is which?
  What about heater wires after they go through the PSU board, and from one tube to the next?

Thanks in advance, maybe it seems like a lot but I think most of the questions can be answered in one word, I just wanted to be thorough.

Thank you for your help, I think that answers all my questions for the moment.
I can finish drilling the chassis, mount and test the TR, wire the heaters.

I'll be back when all of this is done, I suppose!

I'm making good progress, PSU is complete with correct voltages, but it's almost time to wire the output transformer
I know it has been discussed a lot but my question is for 16 ohm output:

Should I bridge 4 ohm taps (3 and 16) and 8 ohms (4-15) ?
So my output is just all the green wires together?

Also can you confirm what another user said about the "mod" pdf:
The picture isn't correct (7and 12 for plate voltage) but the text is (7 and 13)?

Thanks in advance

edit: I'd like to add a question. Shielded wires are shown to be connected to ground. It's the shielding only that should be connected to ground? How do you do that?

So I finished building (I'd like it if someone could confirm I wired the output trafo correctly though)
And I measured my voltages without tubes, most are good,
but in a few places i only get 310v instead of 360:

pin 1 and 6 of V1
and pin 2 of v2.

Thanks in advance to whoever can help a bit. Also lower voltages shouldn't be dangerous for the tubes? Can I put the tubes in and see if it works?