I'd be leery of serrated flange heads not allowing the the freest lateral slip of the cast collars. All lengths are 1 1/2" (IIRC), except the center 4 at 1". There was at least one account in the murky past here that someone's 1 1/2 bottomed out in the head. Then you're hunting 1 1/4", so just check and match what you remove.
But you're right there's scads of threads on this.
\'96SS SOB: SSRI, Herter Tune, Tri-Y II, , 3000 Edge, F/HO bars, METCO extendeds with CV MMC, Bilsteins, currently Vredestein Ultrac Sessanta (315/35 rear). Finally, wait for it... LT-4 knock module!
\'96FWB BUW-Butt Ugly White: PCMPerformance tune, HDFA w/ swissed filter, 1/2 SLP s.s. catback with H- and Flow Super 50s, oem opti rebuilt 3 times, SS Bars, METCO LCA, Airlift 1000, Monroe SS, PowerTrax No-Slip, CTS wheels with +1 rubber. Finally, yes again... LT-4 knock module!