Hand is a made up hand.  Villain opens 30% from the CO to 2.5x, we defend with a range of roughly 25% (shown in picture below).  With an R of 60, we should be defending at least 20%.  The range shown takes away hands we 3bet (QQ+, AK, half of AQs, most JJ, half of TT).  Villain is a solid reg with no other reads.  The flop comes up 9d5c2c.  He cbets 70% pot.

I colored in Photoshop how we proceed with our range, blue is check/call, red is check/raise, and black is check/fold:

Check/call:
All AQs-A9s, A5s-A2s; A8s-A6s of diamonds and clubs only
A9o+, A8o with a club
KQs-KTs of diamonds and clubs, K8 of clubs
KQo-KTo with a club, K9o
QJs, QTs, Q8s of clubs, Q9s
JT of diamonds and clubs, J8, J7 of clubs
T8s, T7s of clubs, T9s
98s, 97s
87s of clubs
76 of clubs

Check/raise:
J8, J7, T7, T8, 87, 76 of diamonds
55, 33

Some key stats that I came up with:

Check/Call Flop - 57%
Check/Call Strength on the turn - 36% (Made up of at least a 9, strong draws, and floats that hit)
Check/Raise Flop - 4.5% (13/295)
Check/Raise Flop Value - 46%
Check/Fold Flop - 38%

Note:- Calling with the KQ-KT combos is when we have a backdoor flushdraw.  Same with A8o.  Actually most check/calls that make sense only with the BDFD is only counting the BDFD (like A6s/A6dd as well).

Questions:
1) We are check/calling way more than raising.  How does this ratio look?
2) Our check/call strength seems to be low.  The 36% number is hands we would have a very high chance of calling the next street, so unless we float a lot more, we will be folding over 60% to the next barrel.
3) Our optimal bluff frequency is over 40%, and in this situation we are over 50%.  Is this too high?  We also have some equity with our bluffs.
4) How would you change this range?