Staking advice please???

i would appreciate any advice here...

i am currently doing a laying system.....
the horses i lay are generally between odds on and no higher than 5/1..... the strike rate is quite consistent but i hit a winner every 8 races or so and some of these are very short odds....

i am keen on using a staking plan to get profit on every race by either doubling up on the next race after a winner or choosing horses at a specific price to regain losses plus a profit i aim for on every race...

i keep a history of all results and could probably highlight certain types of races, track etc where i have a much better strike rate and could wait for that type of a race to regain losses....

hope this make sense, any advice would be greatly appreciated.....