How do I know which standoff screws to use?

How about using 3M Command hooks or tape. You can check their products and see if they have anything you can use

thnx katie good idea.

I have no idea what they are called but check out the screws used at the end of the perspex project. They would look great on your project. https://uniquecreationsbyanita.com/led-headphone-stand/

Command hooks are the way to go if you don't want holes in the walls, Katie.

I don't know if it helps but I have been using Command Strips meant for pictures with pretty good success. You can see them here - https://amzn.to/2TQl3XA

Hi katie, how about a picture hanging rack? It allows several pictures to be hung on it and at different heights if you prefer, hope this gives you soemhelp,

https://www.youtube.com/watch?v=H8LSheYiDgg

Hey Katie, how about mirror clips? They may work for you, I have attached a link for you to check out,

https://www.amazon.com/Yardwe-Mirror-Bathroom-Hanging-Accessories/dp/B07QX4WYX9

https://www.amazon.com/MTMTOOL-Floating-Wall-Mounted-Bathroom-Supporting/dp/B081SY6NV3/ref=pd_day0_hl_201_7?_encoding=UTF8&pd_rd_i=B081SY6NV3&pd_rd_r=77b9da2f-0e5a-458c-ab74-baff585af869&pd_rd_w=eKiMf&pd_rd_wg=5WNCs&pf_rd_p=531c5da2-92c8-47a3-8df6-cb5fa8f00603&pf_rd_r=00DTCJY2Q3SXAJN1JNFP&psc=1&refRID=00DTCJY2Q3SXAJN1JNFP

Hi! I was looking at fasteners that might work for your project. Just a thought, but, what about mirror clips like these?

https://www.amazon.com/dp/B07H9NC9SF/ref=sspa_mw_detail_6?psc=1&pd_rd_i=B07H9NC9SF&pd_rd_w=P8EYJ&pf_rd_p=d00bbee1-7e15-4077-bce3-90f05c1dc9a0&pd_rd_wg=3JMc4&pf_rd_r=DQPDZNQ0K52S1FRK24N1&pd_rd_r=bba2e149-afa1-4a1b-a089-f5e47534e6bc&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzM1hXSkxKTEdWVENKJmVuY3J5cHRlZElkPUEwMzc1MDAzMTY3ODlTOUFBQkhCUCZlbmNyeXB0ZWRBZElkPUEwNzg3NTg5MkE2MjRTN1ZJM0lMRCZ3aWRnZXROYW1lPXNwX3Bob25lX2RldGFpbF90aGVtYXRpYyZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

Hi Katie, you can use "mirror clips" or "concealed mirror clips". These can be used to mount flat items to a surface without requiring holes etc in the piece to be fastened in place. Just look for mirror clips on Amazon and you'll find a whole bunch to choose from. Hope you come right and finish off your project.

I got my standoff hardware on Amazon!

I use command strips for my heavy pictures, they don't create holes in wall. Get the durable ones. Here is a link to https://amzn.to/39J5F6a