Pack66, with all due respect you don't pick up FA that are not part of what you are trying to do. It is the craziest thing you ever have suggested. At any level of football the coach has a VISION of what he wants to do. You get players who are capable of of executing it. No, and I mean NO, coach will let the players dictate what the scheme will be. That's why they are the COACH. Every coach has his system, players that fit that system will be given the opportunity to play within it.
I see this all of the time as a Jr high coach. People think that coaches are interchangeable and that they all are willing to run any kind of system based on what they have to work with. Coaches WILL run different schemes not based on what the OL look like but based on what the backfield looks like.
I will run a zone blocking scheme if it fits into my running game. If I have fast backs, that hit the hole quickly, zone blocking is the way to go. If I have Jamal Lewis back there we will go with a different scheme.
BUT......Either way my scheme will not change due to types of OL I have. It starts with my vision, then goes to the type of RB I have and then I will dictate which system we will run with the line.
Also, in the zone blocking system Allen would not be the Allen you know. He would seldom have to block straight up, would be required to scrape off to LB's and workin unison with younger guys in better shape. No way you even consider this guy.
Its hard to explain to someone who has little experience with working on blocking designs, which I assume you do not. I just don't think you understand the Zone-Blocking concept or how a team is put together. I am not trying to insult you at all so don't take it the wrong way.