From my personal experiences, I don't think you have to worry TOO MUCH about "flagged IP." The reason why I don't believe in it is because how would Jagex handle people that are using computers at the library, public hot spots, university wifi, labs, shared computers etc? Personally I got a ton of accounts banned from my home IP when I was new to the botting scene. However, I have a "legit" main account that I never bot on and it has yet to be banned. I can't speak for the massive scale botters that have everything automated and run 100s of accounts but from a small-scale mid/high level tier botting perspective, I found a nice balance of one or two accounts per computer was the way to last the longest. No Proxy, VPN tinfoil BS. Only time I would use proxies/vpns would be when I have accounts that are ready to bot high-end content such as barros/zulrah and I'll exclusively bot that on a specific proxy until they get banned and recover it from creation IP. From Jagex, account review end, it'll look like the account "got hacked."
Probably gave away a nice "secret" that many experienced botters use. In regards to the accounts getting banned from manually doing tut, etc on a osbot client, I had a similar experience. For some reason, I was getting banned for manual completion on bot clients. The reason why I said you don't have to worry too much about "flagged IP" is that I found that a mixture of completing tuts by hand partially on an official client and finishing the rest with any tut script was good enough to get the account through the first day. I believe flagged IP does play a factor but it seems more of a 95% pattern recognition:5% flagged ip ratio for bans.
just my two cents! Hope y'all have better results with botting from my insight. Doesn't hurt to try ?