Spear + Gold					No Chests					Spear + Gold + Morning Star
Target	Frames	Gold	Frames/1000	Frames Adj	Time Adj	Gold/1000	G/FA	Trips for 7k	Trips w/ Deci	Frames	Frames Adj	Time Adj	Trips for 9k	Trips w/ Deci	Frames	Frames Adj	Time Adj	Trips for 6k	Trips W/ Deci	Frames	Frames Adj	Time Adj	Target
1250	2687000	699658	2687	7487	2:5	700	0.093495	10	10	26870	70070	19:28	13	12.9	34931	92531	25:42	9	8.6	24183	62583	17:23	1250
1300	2911860	878238	2912	7712	2:9	878	0.113849	8	8	23296	56896	15:48	11	10.3	32032	80032	22:14	7	6.9	20384	49184	13:40	1300
1350	3133980	1080768	3134	7934	2:12	1081	0.136249	7	6.5	21938	50738	14:6	9	8.4	28206	66606	18:30	6	5.6	18804	42804	11:53	1350
1400	3420514	1234622	3421	8221	2:17	1235	0.150225	6	5.7	20526	44526	12:22	8	7.3	27368	60968	16:56	5	4.9	17105	36305	10:5	1400
1450	3804297	1380012	3804	8604	2:23	1380	0.160391	6	5.1	22824	46824	13:0	7	6.6	26628	55428	15:24	5	4.4	19020	38220	10:37	1450
1500	4248575	1648496	4249	9049	2:31	1648	0.18212	5	4.3	21245	40445	11:14	6	5.5	25494	49494	13:45	4	3.7	16996	31396	8:43	1500
1550	5178390	1948299	5178	9978	2:46	1948	0.19523	4	3.6	20712	35112	9:45	5	4.7	25890	45090	12:32	4	3.1	20712	35112	9:45	1550
1600	5887943	2107915	5888	10688	2:58	2108	0.197231	4	3.4	23552	37952	10:33	5	4.3	29440	48640	13:31	3	2.9	17664	27264	7:34	1600
1650	6841959	2354429	6842	11642	3:14	2354	0.202199	3	3	20526	30126	8:22	4	3.9	27368	41768	11:36	3	2.6	20526	30126	8:22	1650
1700	8751482	2600031	8751	13551	3:46	2600	0.191868	3	2.7	26253	35853	9:58	4	3.5	35004	49404	13:43	3	2.4	26253	35853	9:58	1700
1750	11263762	2943922	11264	16064	4:28	2944	0.183267	3	2.4	33792	43392	12:3	4	3.1	45056	59456	16:31	3	2.1	33792	43392	12:3	1750
1800	16340797	3351832	16341	21141	5:52	3352	0.158554	3	2.1	49023	58623	16:17	3	2.7	49023	58623	16:17	2	1.8	32682	37482	10:25	1800
1850	27490654	4231248	27491	32291	8:58	4231	0.131027	2	1.7	54982	59782	16:36	3	2.2	82473	92073	25:35	2	1.5	54982	59782	16:36	1850
1900*	88398674.8	7874088	88399	93199	25:53	7874	0.084486	1	0.9	88399	88399	24:33	2	1.2	176798	181598	50:27	1	0.8	88399	88399	24:33	1900*
* 1900 projected to 1000 based on 409 results; I don't know if I'll update this later after the script runs more trials.
Conclusion: Shocker, 1700-1750 seems to be a good range.  1650 is "ideal" 50% of the time when you get average-or-better luck, but you don't want to take a fourth trip, and more gold to start the next segment is good.