PDGA standard for disc approuval says :
(3) not be less than 21 cm in outside disc diameter, nor exceed 30 cm in outside disc diameter;
(4) not exceed 8.3 g per cm of outside disc diameter;
(5) not exceed a maximum weight of 200 g;
You're not gonna find a conventional style small diameter putter over 175g, maybe 178g but marked wrong, tops. Larger putters may weigh more but won't act like they do they actually 'feel' lighter usually due to the large size.
A. Discs used in play must meet all of the conditions set forth in the Official PDGA Technical Standards Document. See section 805 B for disc technical standards.
B. A disc which is cracked or perforated is illegal. See sections 802.01 D, E and F. A disc which is cracked during a round may be carried by the player, but not used, for the balance of the tournament. The player must immediately declare his intention to carry the newly cracked or broken disc to the group or be subject to penalty under 802.01 E.
C. Players may not make post-production modification of discs which alter their original flight characteristics. This rule does not forbid inevitable wear and tear from usage during play or the moderate sanding of discs to smooth molding imperfections or scrape marks. Discs excessively sanded or painted with a material of detectable thickness are illegal. See sections 802.01 D, E and F.
D. Discs must be specifically approved by the director if questioned by another player or an official, but in no case shall the disc be approved if it violates any of the above specifications. Any specifically non-approved disc (per the director) shall be considered illegal, and the player shall be penalized in accordance with 802.01 E.
E. A player who carries an illegal disc during play shall receive two penalty throws, without a warning, if observed by two or more players of the group or an official. A player who repeatedly throws an illegal disc during the round may be subject to disqualification in accordance with Section 3.3 of the Competition Manual.
F. All discs used in play, except mini marker discs, must be uniquely marked in ink or pigment-based marking which has no detectable thickness. A player shall receive a warning for the first instance of throwing an unmarked disc if observed by two or more players of the group or an official. After the warning has been given, each subsequent throw by the player with an unmarked disc shall incur one penalty throw if observed by two or more players of the group or an official.
i think they're fine rules. it's similar to ball golf in the fact that if you broke a club (snapped the shaft) you would not be able to use it legally.
the two penalty strokes for carrying an illegal disc would be similar to carrying a driver that is not usga legal (even if you had no intention of using it). these kind of rules take out the human error, meaning you can't know if someone actually had the intent of using the disc or club, so by making it illegal to carry a disc or club that is non-conforming, it adds legitimacy to the round and the sport.
not really a big deal