The biggest difference between tighthead and loosehead isn`t in the ankles mate, but in the technique required. Granted, it`s probably a lot easier to move from tighthead to loosehead than from loosehead to tighthead, but still- your binding arm changes, your angle of entry (no, no, no, this is NOT a sexual statement!) on the engage changes, all of a sudden you`ve got to get the "long bind" over your opponent in order to minimise his chances of getting the right shoulder- provided the ref allows this. So it`s a completely different ballgame at 1 than at 3.
On the plus side, it`s much easier to be a powerful scrummaging 1 than a 3. Remember that the 3 has to take pressure from both the 1 and 2, whereas you`ll get support from your hooker when going for the "roll" on 3. Plus your hooker can also "bore in" on the opposition 3, provided the ref allows it.
Another point to consider- seeing as you`ll be required to basically do less work during the actual scrummaging itself, plus you`ve got a quicker route out of the scrum once it`s over, you`ll be required to get around the park a bit more, make more tackles, hit more rucks and carry the ball up more if you`re playing loosehead. So if you do make the shift, maybe look at spending less time in the gym doing squats, and more time on short, sharp sprints.