12s3p battery help

Hows it going everyone… I’m looking for some suggestions for the best 12s3p battery up to $400… So far for this springs build I’ve bought Dual Flipsky 6374(Battle Hardened) motors, the FOCBOX Unity, Torque Board Trucks, Torque Board V7 motor mounts, Torque Board 90mm wheels, 20T motor pulley, 32T kegel Style pulley and Dragon “race” bearings… Next step is to finally choose a battery for this thing… My goal is to get into the 45mph-30ish mile range… Does anyone have any suggestions for a 12s3p battery that will get me in this ballpark for $400ish. O yeah, I almost forgot the curve ball… I’m running this on a 30” Meepo Mini 2 Deck so I have just about 19 inches between the trucks to mount the battery and the FOCBOX Unity which is 3 inches, so I have roughly 16” in length available space for the battery… Any thoughts on these two batteries both will fit but i like to get the best I can with your guys/girls help…

Mboard 12s3p Specs

Nominal Voltage: 44.4V Capacity: 9000mAh Power: 388.8Wh Continuous current: ??? Max current: 45V Cells: Samsung 30q

Backfire 12s3p Specs

Voltage: 43.5v Capacity :10.5AH Power: 454WH Continuous current: 30A Peak current :45A Cell: Sanyo NCR18650GA

Thank you for you help…