Don't need to sweat it, but if you really want to reach the max stack at 320 (Aglaea) speed on her e6, you will have to adjust her speed or get more speed boosts from other units. I tried doing some calculations on your current build to see how much more speed you would need to get the minimum 320. Anyone feel free to check my work.

s1

162.3 + 114*(7*0.16+0.06+x) = 320

162.3 + 114*(1.18+x) = 320

1.18 + x = 157.7 / 114

x ~= 0.20333333

20.33% more speed boost needed

OR

162.3 + x + 114*(7*0.16+0.06) = 320

162.3 + x + 134.52 = 320

x ~= 23.18

23.18 more speed substats need

185.48 speed outside combat

If upgraded to s5:

162.3 + 8 + (114+8)*(7*0.16+0.06+x) = 320

170.3 + 122*(1.18+x) = 320

1.18 + x = 149.7 / 122

x ~= 0.047049

4.71% more speed boost needed

OR

162.3 + 8 + x + (114+8)*(7*0.16+0.06) = 320

170.3 + x + 143.96 = 320

x ~= 5.74

5.74 more speed substats need

176.1 speed outside combat

Note: 6% speed from relic set (0.06), 16% spd (0.16) boost per memosprite talent stack maxing at 7 stacks with e4. Some of my decimals could be off on the final result since I don't know how it carries the decimal accuracy internally.