Question about replacing 12AU7 tubes.

I am new to tube amps and have a question about the 12AU7 tubes in my Dared VP-300b Quasi Monoblocks. Each of them has a 300b tube and 2 12AU7 tubes.
I would like to have a replacement at hand if a 12AU7 tube goes out (also read somewhere the stock tubes are not that great).
Do I need to get matched pair or even 4 matched tubes?
If matched pairs would I put one matched pair in one mono block and the other pair in the other, or would I put one of each pair in each mono block so they have the"same" kind of tube combo?

Any suggestions about this and any tube suggestions would be appreciated?

All ways's replace in matched pairs. I get NOS RCA from Brent Jesse, he has a good reputation with me and others on this forum. Never get STOCK 12AU7's, they don't last as long or sound as good.
Matched pair, or even better a matched quad. As far as actual 12AU7's go I've always been a big fan of Mullards, Amprex, and Telefunken. In fact if you keep an eye on the for sale listings you will probably find what you're looking for..
For your information,a 12BH7,5963,5814 can also replace a 12AU7. So if you find those types matched you can use them.
Your VP 300B amps have a single 12AU7 driver tube, and a single 12AU7 input tube. You do not have to use the same type of 12AU7 for both positions. You should, however buy two matched pairs. Amperex 12AU7's and 7316's are excellent tubes, as are the older black plate CBS/Hytron/Raytheon 5814's. I would not suggest Telefunken 12AU7's....For some reason, Telefunken made a lousy sounding 12AU7. Their 12AX7's and 6922's were amazing though! Try a pair of the CBS 5814's as drivers, and a pair of Amperex 12AU7's for the input tubes....A great sounding combo!
Thank you all for your input. I apologize for my ignorance, bigshutterbug, but how can I tell which one is which of the 12AU7 tubes. Does one have more influence on the sound than the other?

One of mt favorite 12AU7 is the RCA Clear Top, side Getter, very open tube with excellent dynamics.
Anybody got an idea for a supposed up-grade for a 6z4 recitifier power supply tube?
I disagree with Bigshutterbug. I have large stock of 12AU7s; new and vintage. Telefunken are my favorite vintage tubes. Among new tubes the EH 12AU7s are very nice, but the Psvane 12AU7s are fantastic. I'm starting to lean more toward Psvane even over the Telefunkens. Warning, the Psvanes take about 100 hrs to reach their ultimate quality. First few hours they sound a little on the soft side and they were not competitive with the Telefunkens.
Brf, mine too.
Both the driver and input tube will have a noticeable influence upon the sound of the amps. I could not find any info on the net in regards to which is which. Does your manual say anything about them? I'm sure Dared could tell you if you have an e-mail for them. Have fun!
My experience with 12au7's is as follows- Mullard is my favorite, followed by RCA clear tops. When you factor in price, the RCA clear top is a bargain.
Thank you all for your input. I will think about what tubes to order as a backup/rolling ensemble. I also have not been able to find info about which tube is which for the 12AU7s. I will try to send them an email

I was fortunate enough to get some gently used Sophia Princess Mesh 300b tubes and had ordered new Tesla ECC802S tubes with PLATINUM pins.
When all the tubes were in, I could not tear myself away from the beautiful sound (some Stacy Kent, Patricia Barber, Diana Krall, Ella Fitzgerald, Johnny Hartmann, Gillian Welch and more) and also could not get the big smile off my face.
I definitely want to get some backup tubes because I cannot imagine being without this if a tube should go.
When I first got my VP20 I went a little crazy with tube swapping. My favorite 12AU7 ended up being a set of Sylvania 12AU7WA mil spec tubes I bought on ebay. I knew they had never been opened as they came in the boxes I remember tham coming in back in the day when I was an electronic tech in the Air Force.

Actually, the nostalgia of seeing those old boxes with the federal stock number may have had a positive influence on how I heard them. They seemed to have the cleanest sound of all the tubes I tried and I have read on other forums that those particular tubes can sound less "tubey" because of their clean high frequency presentation.
I was thinking about picking up a pair of those Dared VP-300B to power my tekton speakers. How do they fare against the previous amps you were using? Are you coming from solid state or something else?
Before the VP300, I was using the Peactree Nova as my DAC, Preamp and Amp. I am still using the Nova as a DAC and Preamp, but have replaced the Amp section of the Nova with the VP-300b.
I have not done a side by side comparison, but my impression is that the Soundstage has improved (clearer), and the detail I perceive in the music has increased. Almost like a layer between me and the music have improved. While I feel that all music has improved, I find female vocalists particularly stunning (Stacey Kent, Patricia Barber, "les moulins de mon coeur" by Carmina and many others).
Be aware that the VP-300b comes without 300b tubes.