To be honest, whether you're starting for fun or for serious, there are a lot of cheaper but solid options (basically better all around) out there that will grow with you than this looks to be.
Gain shouldn't be the problem and I wouldn't suggest manual mode. I'd def look into what bensid54 suggested and try it on level ground. If you've already done so, then yeah, we need more details.
Not new to multis but I've always been a buy it and fly it kinda guy so I've never done a real build before.
Also looking for some groups to join in my area. I run a small drone related forum as well so I'm hoping to meet new friends and expand my knowledge so I can help folks there too.