From my experience with the Mnats 1176 Rev D so far that you may find useful.
Buy alot of certain transistors that require to be matched or reach a certain hfe. I'm not talking 10-20, Im talking somewhere in the hundreds since Mouser seems to be the only place to source decent versions of these transistors and the hfe reading on these is hard to get above 250.
Get a decent multimeter with hfe reading.
Be careful of abundance in shipping costs, it tallies up when you have to keep having to re-order parts so try to order in one go.
DIY is not going to be cheap and very time costly and can get frustrating.
Regarding the BOM, re-check the parts list, because some of it has dead links or parts options. I have an Exell sheet for the Mnats 1176 Rev D if you want a copy. I haven't refined it fully, but maybe you may find it useful. It has markings, notes, tables, links etc, trying to make it useful for printing and progress and it can be edited.
Check the attack pot in the BOM list, make sure it has SPDT if you want that GR off function on the attack pot.
Purushas case for the 1176 has a back inside plate that may make it tight for the pots and may require for you to sand it down or make a cut out. Mine was a tight squeeze when I removed the washers from the pot, but it fits now. The IEC hole requires an IEC with fuse preferably the snap on type (though a little lose fit but still covers it enough) and not screw type for a better fit. The pots in the current BOM are a little small for Purusha's 1176 case.
Purusha's case does not come with any documents, nuts, washers for the mounts in the inside plate that holds the push buttons.
Get your nuts, bolts, screws, washers, etc from a dedicated nuts and bolts store. From my experience, they are the most cheapest places to get these parts specially at small bulk or singles. Do not buy them from electronics or hardware stores. The mark up is ridiculous! Get washers, lock washers, spring washers, nuts, lock nuts and bolts in sets and they work out very cheap at these places.
Do a run down of all the nuts, bolts, washers, you plan to use. This includes XLR ins and outs nuts/bolt/washers sets, also washers for the inside plate on Purusha's 1176 case. Also washers for the spacers to hold the PCBs, nuts/bolts/washers for the Xformers, Cable ties/clips/mounts nuts/bolt set (I bolt mine).
Invest in a small engraver with different attachments. See the little lip on the pots that prevent the pot from moving when you mount it. You need to dig a little hole for that so that the pot does not move when secured. One way is to use a broken drill bit of the same size as the little lip and adjust the depth the drill bit is porturding from the drill according to the lip depth and drill a hole for it. I use a combination of drilling a hole and then finishing it off with the engraver so that it does not go thru all the way of the front face of the case. If you have a Drill press, it would be better.... 8)
Check measurements of parts in the BOM list. Some of the caps are too big and creative installations on the PC board if you get those sizes.
Mnats Transformer board requires links if you are using altran transformers. The ABCDEF is located on top of the board underneath where the Altran Xformer goes, so links up first before installing the Xformer.
Resistor Bend tool is very useful, makes things more productive. Recommended must have or make your own.
Alot of the information is scattered in various threads. They have an "all in one thread" which I have my own opinion about this system, it's where you will find the information scattered. Some goes from 40 + to 100+ pages. Some information you have to source from different threads. eg. G1176, Rev D, Rev A, etc. threads which can be a little confusing or overwhelming.
To search inside one thread, requires you to print and use the browser find function to search for what you are after.
The bottom next and previous button takes you to the next thread and not the next page.
When sending a private message and the person replies, you have no idea what they are replying to because the forum does not keep the sent messages unless you save your sent message into your outbox. Your messages box can get full rather quickly. You have limitted message capacity here and it is best to use email.
Check out Drips format for his builds http://dripelectronics.com. His DIY is more beginners friendly format but it's mostly Tube gear he works with. La2a, 175b, etc.
Check out some of my "newbie" forum questions, maybe theres something there useful. Feel free to email me if you like and I will send you some info and links I already went thru in this process of DIY.