Velocity stacks lenght question

[LAC99]

I want to buy the toda straight trumpets (air horns, velocity stacks or whatever you want to call them) but I don´t really know which length I should get. They have 30 and 55 mm for the silvertop 4ag.
I have standard camshafts, custom 4-2-1 header, 11:1 compression and a port & polish job. Blacktop ECU and MAP. Everything else stock.

When I tried 63mm trumpets I felt more medium range torque but less high end power than with the stock parts so I want to shorter ones but I don´t want to lose to much medium range torque if I go with the 30mm

Do you know if there´s any dyno chart or something I can check out to compare the power/torque curve with different trumpet lengths? what experience do you have with different lengths? Is it best to use the horns with or without the air box?

thanks,

Luis