Admin of a 'Line-Up"

[Ref Daddy]

Last night boys 9th grade. Massive substitutions all night long.

Dead ball out of bounds late in game 7 subs come in, 4 home and 3 visitor.

Following the rules the speaking captain politly asked me for the opportunity to have a line up. I recalled that 3 or more substitutes qualified, the ball was dead - so we were going to "line up".

Anyone recommend or know of a proper mechanic for the line up? Where? Jump circle? Half court set?

I had the players quickly line up parallel to one another and they kinda pointed - I got him, you take him thing ensued.

Advise.