I prefer to run seperate fused power for injectors and coil(s) but you _should_ be ok. Do reduce the MS fuse from 5A to 3A though, safer that way. What I am doing on my new (for me) car is running 2 EFI main relays. Each one is rated at 40A and powers 4 ATO fuses. This way I can run a seperate fused power circuit for MS, injectors, coils and various other electrical components under the hood.
92 Corrado 2.0L ABA on MS3Pro. Support the developers! Sandy Linfert 11/4/91- 5/13/13