You're looking for the Dexter E-Z Flex Suspension Kit - Double-Eye Springs - Tandem Axle - 6,000 lbs # K71-652-00, which will fit on tandem axle trailers with 33" spacing between the axles (measured center on center of the axle-as you did). This is a complete equalizer upgrade kit that comes with cushioned equalizers, shackle straps, wet bolts and bushings you'll need to upgrade from your standard equalizers.
I've linked a review and installation video of this kit for you to check out, as well. view full answer...
From what you described it sounds like you're needing the T-Fitting # 103602-MBS along with the Fill Hose # 100019-144 (for your small tank), the Tank Connector # 204037-MBS, and the 2-Stage Propane Regulator # 108221. Attached is a photo of what this setup looks like and below is a full list of the parts you'll need if all you currently have is the 100 lb tank:
T-Fitting - # 103602-MBS
Fill Hose - # 100019-144
Adapter Hose - # 100284-144-MBS (for an appliance like the Grill # FR51322)
Tank... view full answer...