Looking for midi and maxi plasmid isolation protocols from E coli (high copy number plasmid) cultures above 100ml (LB)

Protocols tried so far:

Sambrook's midi and maxi prep

Alkaline lysis method

Boiling-Lysozyme-IPA-EtoH method

PEG mediated plasmid isolation procedures.

Issues consistently facing:

Not able to completely avoid Genomic DNA during bulk plasmid isolations (Though plasmid is present in eluted sample).

Sometimes experiencing RNAse contamination (even after RNase Treatment what about using Lithium Chloride to get rid of RNA during lysis step and neutralization step). Are there any standard ratio for pellet weight to RNAase concentration to be used

Precautions taken/modifications:

Considering the lysis step being important in denaturation of genomic dna and plasmid dna, we did try giving very less incubation time ~1min for lysis step and compared it with 5 min incubation with lysis. In both cases only the amount of genomic DNA was high in 5 min incubation. and for both lysis and neutralization steps care was taken to invert mix gently with out giving any chance for shearing Chromosomal DNA.

Apart from using any commercial kit methods for midi and maxi, are there any inhouse developed or in practice protocols please share links/procedures

Downstream application of bulk plasmid:

Restriction digestion alone.