If you have a delay of 30s (or higher), use both search engine options and have a reasonable amount of proxies (at the very least 5 per search thread, preferably 7+, and at least 20 proxies) you shouldn't have any problems.
I have found that users trying to search with 5-10 proxies have issues where users with 50 or more rarely do. There are some more proxy controls coming in the next update that will make handling proxies slightly better (especially when dealing with
proxy checker software) and I will be accompanying the latest update with some new guide videos to show the newer controls and how to get the most from them.