First of all I'm sorry if my english is poor or the sens is a bit fuzzy, im a french canadian from Québec and we don't really speak english there! (A bit more in Montréal) but anyway!
To make a short story I'd like to get a runic tattoo, it will be the "Othila-Isa" bind rune (like the emblem of runemaker website), circled with 7 words of power around it, and I was wondering, does the words of power will all have their full effecs or the power will not be at its greatest because there'll be too much of them at the same spot. And should I use the double dot ":" or the cross "+" to seperate them, as a space.
I have to disagree with you about Quebec. I lived there for many years and found it very difficult to learn Quebecois French - as soon as people heard my English accent everyone wanted to practise their English on me! Except in Montreal - that was the only place they allowed me to speak my dreadful mix of English-schoolboy-French with Belgian slang. I guess they thought it sounded pretty funny. Or maybe your compatriots are more tolerant of genuine Brits than they are of English-speaking Canadians.
All that aside, The bindrune logo of the Rune Tattoos website is actually my initials RWO rendered as Raido-Othila-Wunjo. It also happens to be a traditional bind representing "Realization of Ambition". I chose variants of that bindrune for many of the Runemaker Group websites because it had been a longterm ambition of mine to publish a rune-related website and offer my runic products for sale.
To answer your question, the elements of any runic design can be empowered as individual runes, as bindrunes treated as a single entity with a specific intent, or as words with a specific meaning. The only possible area of conflict in your proposed design will be the positioning of the words in relation to the central bindrune and to each other. I suggest you seek some expert help in that regard, it isn't always easy to see the conflicts or ways to overcome them.
I do undertake such commissions for customers but it is not a free service, and I am not taking on new work right at the moment because I have a backup of orders on the waiting list. If you want to discuss that further please email me.