Honestly, I Blindside more on Archer in conjunction with Multishot than I do on Pugilist. Since I got Follow-Through though I do use them together. I'll get online and do some testing right now. I have Blindside I & II so I'll mess with both on Pugilist, then mess with both on Archer w/o Seasoned Veteran, then again with.
EDIT: I put positioning in brackets. My initial run was on the R1-3 Marmots right outside the city however my one Blindside did [Critical! 864, 864, Critical! 864] and I immediately scrapped that data.
R32 Thickshell
[Rear]Flurry – [201, 183, 184]
[Frontal]Flurry[196, Miss, 187] [191, 190, 189] [195, Miss, 185] [195, 183, 194]
R31 Thickshell
[Rear]Blindside + Flurry – [Critical! 287, 259, Critical! 295] (Obvious damage increase even on the non-critical)
[Frontal]Blindside + FollowThrough – [1497]
R34 Thickshell
[Frontal]Blindside II + FollowThrough [1122]
R32 Thickshell
[Frontal]Blindside + FollowThrough [1312]
R33 Muy-Tun Squirrel
[Rear]Flurry – [Critical! 363, Critical! 367, 316]
[Frontal]FollowThrough [1683]
R33 Muy-Tun Squirrel
[Rear]Flurry – [326, Critical! 354, 306]
[Frontal]FollowThrough [1837]
R30 Muy-Tun Squirrel
[Frontal]FollowThrough [2038]
R33 Muy-Tun Squirrel
[Frontal] Blindside II + FollowThrough [1829] (No damage bonus. In fact, it did a bit less)
So I mean while this isn’t extensive testing, it’s just an idea. I avoided testing with Victimize II since I don't feel like constantly building to 3k TP specifically to use it atm but I can test it along with Flurry and FollowThrough more extensively on Monday.
And if you're interested, I have
84STR
137DEX
I'm using Peiste Cesti +1.
EDIT2: I don't know if you noticed it in your testing and I didn't during the R34s because I wasn't on them very long, but during the Marmots, using Blindside had a pretty noticeable increase on the critical hit rate. It might've just been coincidence though.