What is the best profile for a Sim Rig

What is the best profile for a Sim Rig

Aluminium Series Profiles are very confusing to many Sim Rig builders. But it's honestly easy to understand, once you understand a manufacturers terminology.
In Europe, Asia & Australia it's typically only possible to buy metric extrusion, in North America we can buy Metric or Imperial with imperial being the most popular.
The two common bolt diameters are 6mm (1/4") or 8mm (5/16").
In Europe, Asia & Australia, your local supplier may not use the name "series", so you need to understand the suppliers terminology. I first look at the bolt size offered, if it uses 6mm bolts then the series is based multiples 10mm or 20mm or 25mm, this is light to medium duty profile.
If the extrusion uses 8mm bolts then the series is based on 30mm or 40mm or 45mm, this is a medium to heavy duty profile.
Metric Extrusion Profiles
  • 25 series is based on multiples of 25mm
    • 25mm * 25mm or 25mm *50mm, 50mm * 50mm, etc
    • T-Nut & bolt size 6mm
  • 30 series is based on multiples of 30mm
    • 30mm * 30mm or 30mm *60mm, 60mm * 60mm, etc
    • T-Nut & bolt size 8mm
  • 40 series is based on multiples of 40mm
    • 40mm * 40mm or 40mm * 80mm, 80mm * 80mm, etc
    • T-Nut & bolt size 8mm
  • 45 series is based on multiples of 45mm
    • 45mm * 45mm or 45mm *90mm, etc
    • T-Nut & bolt size 8mm
Imperial Extrusion Profiles
  • 10 Series is based on multiples of 1"
    • 1" * 1" or 1" * 1 1/2" or 3" *  3", etc
    • T-Nut & Bolt size 1/4" or 6mm
  • 15 Series is based on multiples of 1 1/2"
    • 1 1/2 * 1 1/2" OR 1 1/2" * 3", etc 
    • T-Nut & bolt size 5/16" or 8mm
Many of the above series are also available in different wall thickness. So if you find a bargain price rig or extrusion check the wall thickness! Extra light has a very, very thin wall thickness.
If the rig is designed correctly and well braced like the Evo Supersport full bracing, you will experience almost zero flex even with OSW * HPP pedals. I own and use a 25 series rig and see no reason to go to the much thicker, heavier and more expensive profiles.
Good design choice of the appropriate size extrusion is critical, for example a triple monitor stand built totally for 10 series or 25 series can be very strong OR too light & flimsy depending on the section you choose! I would suggest 50mm * 50mm OR 2" * 2" builds a very good monitor stand, but 25mm * 25mm or 1" * 1" would build a very poor quality stand.