I think I missed something, I did not know your goal was 28 inches with a 43 inch bow,,
20 inches with a working handle would be reasonable draw,,
if you want a 50# bow from that you would need to sinew back it,,flip the tips a bit,,
and it might go 21 or 22 inches,, make the handle work,, and it might go a bit further,,
but the sinew backing will increase your odds of getting a heavier bow....
if you like short bows, dont be discouraged, they shoot well and are fun and effective as a hunting bow as well,,