If I may toot my own horn, I created just such a website as this question addresses. The website consists of only 3 "pages":
1) A Home Page, with the methods of search to choose from;
2) An Options Page, that provides the options of that method you chose;
3) A Results Page, or your "Hit list", listing all the matches.
Doing it this way, and keeping global variables on the Home Page, this website I hope is intuitive or user-friendly.
It's always in development because I'm just a one-man (retired) operation and when I feel like it or think of something new, I'll dabble in its further development. Thankfully I now have the whole Tanach as the database. All that other "gematria sites" can do, this one can do better.
The website sits behind a yeshiva firewall so you must type in the "http://" instead of the "www." (http://toraware.com)
A next stage of development will be to convert it to an app, but my knowhow there suffers. (I'd love some help if someone wants to volunteer.)
Other future things I might do is: Expand the database to include the Kri version. Right now it's the Ksiv version only. If someone can think of other paradigms of search, do please let me know. If it's good, I'll love to develop it.
You can follow my developmental process because I record my progress, as I go along, on this blog: torawaredotcom.blogspot.com