So after reading both threads, I'm a tad confused. Was a standard rail ever decided on for each of the button sizes? At what point in rocket size does one move from the micro to the mini button?
There are a couple options:
Mini Rail buttons now available from Randy work perfectly with 20mm x 48" rails available from McMaster-Carr and others these 8020 rails are .787" square. I prefer the two slot on opposite sides over the 4-slot as it is Stiffer. McMaster Cat #5537T117 is the one I purchased 13.09 Plus 5.48 S&H.
Micro Buttons work exceptionally well with "MakerBeam" 10mm x 900 (.3937" x 35.43"long) Available from Amazon.com in 2pks. these two pks in black anodized alum. were 19.83 Plus 5.40 S&H making each rail about 12.62.
Amazon is now offering 10mm x 1500mm (.3937" x 59.05"long) Black anodized alum. rails also in 2pks. for 27.00 plus ups.
Over the last few months several of us have been experimenting with these rails using increasing motor levels to see where one should go from one size to another.
To my way of thinking If you're flying BP motors only. it is possible to fly 1/8A- F for the same 10mm rail using micro rail buttons.
if using lower power APCP motors E-F & G's should be flown from a 20mm rail with Mini-buttons. beyond that I have no idea as I do NOT fly APCP period.