Quick box tune questions

[gtkid]

Going to switch my 87 street tune over to my 91 performance tune. How many tanks of 91 should run threw my 87 tune before i switch over to my 91 tune? Is it really necessary to connect my battery to a charger while loading the new tune? Thanks in advance!!

 

[Wes06]

I'd probably run current to e, fill up. Run that low then fill up again and call it good