Just want to clarify: are you using a full bed of Yonex Poly Tour Pro 1.25mm in a Babolat Pure Aero? If your elbow is feeling pain and you are having to use ice packs with 1.25mm PTP, 1.30 PTP mains / 1.25 PTP crosses are only going to make this worse for pain. Reading your post gives us a clear picture of your level, your frequency of string breakage, and the pain you are enduring. Just want to be clear, you are at a level I am not used to stringing for honestly. Current Division One college players in their early 20s are my highest level players and they are all still using stiffer polys.
At your level given your current golfers elbow, it seems you have two (maybe three) non-medical options going forward:
1) switching frames to something with a denser pattern (18x 19/20 or 16x20) and a lower RDC (which you are already considering)
2) using softer strings and restringing even more frequently than 3 hours
3) NG / smooth poly
Going with Option #1
The 18x20 frames like the Yonex Pro 97HD 18x20 with its 59 RDC strung with softer thicker strings such as Tecnifibre HDMX 1.35 mains and a string like YPTA might give you the comfort you are looking for and a little more time between string breakage.
www.tennis-warehouse.com
If you are sticking with any 16x19/20 patterns perhaps consider these also:
The Clash 98 2.0 (16x20) with an RDC 60
www.tennis-warehouse.com
Babolat Pure Strike VS (16x20) with an RDC 63
www.tennis-warehouse.com
But avoid the
Babolat Pure Aero VS (16x20) RDC jumps to 67 (so IMO, this is the wrong direction to go as the RDC has a direct correlation to the pain your elbow is feeling)
www.tennis-warehouse.com
Going with Option #2
Hoping this option might give you both comfort and 4+ hours before breakage
Highly suggest trying Hyper G Soft 1.30mm / Ghostwire 1.27mm
SOLINCO HYPER-G Soft Playtest Application period is closed. Selected playtesters have been notified by email. Your strings will ship by Friday Oct 2 DEADLINE: Monday November 9th NO HYBRIDS Include the following in your review: Gauge received Tension used for playtest Regular string set...
tt.tennis-warehouse.com
If you are snapping YPTP 1.25mm in 3 hours, in order to get more comfort, you have to find softer strings, or a softer frame.
Option #3 (something you should try for once)
Yonex 18x20 Pro 97 HD with
1.35mm Natural Gut mains and a slick smooth poly cross like (GhostWire 1.27mm, YPTP 1.30mm or Yonex Poly Pro 1.30mm)
Keeping the crosses as close the diameter of the Natural Gut in the mains will minimize the sawing.
I would suspect the 1.35mm NG with an 18x20 pattern would give you the comfort you seek and hopefully 4+ hours of play before breakage.