Building a 300 meter rifle system

[Narendra]

I am preparing for participating in 300 m ISSF competitions in 2012 in India, and want to build a rifle system. I have a few questions, and would deeply appreciate your comments / inputs / suggestions.

The rifle is the IOF 30-06, a sporting rifle based on the Sauer 202. I know its not the ideal rifle or calibre, but imports are restricted and target rifles are sold at a very high cost.
Length of barrel = 24 inches
Grooves = 4
Twist rate = 1 in 10 (i think)
Pushfeed mechanism with 3 locking lugs
Bolt locks directly with the barrel
This rifle is known to shoot 5 shot sub-MOA groups with off the shelf 180 grain S&B ammo from a cold barrel.
The rifle comes in a two-piece stock. Being a tinkerer, I will free-float the barrel, lap the lugs, pillar bed the action etc to maximise accuracy. What more should I do to increase accuracy? Handloading ammo is not an option, although I would have loved that.

To build a 300m system around this rifle, I will need sights and a harmonic tuner.

Sights - I have a shortlist of two - either the Anschutz 7020 or a mix and match set of Warner rear plus Scott Riles front, with Gehmann apertures for both. I very much want your suggestions on this, as this is what I am least confident about. I have read that front diopters are good, but because they are lenses, I think they will be illegal in ISSF matches.

Harmonic tuner - I am building one for myself based on a micrometer screw, with a hollow sleeve that clamps on the barrel and weights moved by a thimble. The front sight will be mounted on the sleeve. I plan to make lots of 10 and 20 gram weights to mount on the tuner. Again, your thoughts on this will be appreciated.

Other accessories like a spotting scope I can manage to borrow from friends...

~ Narendra